diff --git a/game.lua b/game.lua
index 5fb7fed..8dfdfab 100644
--- a/game.lua
+++ b/game.lua
@@ -6,7 +6,7 @@ local base = string.gsub(@@LUA_SCRIPT_FILENAME@@, "(.*[/\\])(.*)", "%1")
 local mathFunctions = dofile(base.."/mathFunctions.lua")
 local config = dofile(base.."/config.lua")
 local spritelist = dofile(base.."/spritelist.lua")
-local util = dofile(base.."/util.lua")
+local util = dofile(base.."/util.lua")()
 local mem = dofile(base.."/mem.lua")
 local _M = {
     leader = 0,
diff --git a/neat-donk.lua b/neat-donk.lua
index 0d9ccde..cddc956 100644
--- a/neat-donk.lua
+++ b/neat-donk.lua
@@ -4,7 +4,6 @@ local gui = gui
 local base = string.gsub(@@LUA_SCRIPT_FILENAME@@, "(.*[/\\])(.*)", "%1")
 
 local pool = dofile(base.."/pool.lua")
-local util = dofile(base.."/util.lua")
 
 local statusLine = nil
 local statusColor = 0x0000ff00
@@ -30,4 +29,10 @@ pool.onRenderForm(function(form)
         gui.text(-500, guiHeight - 20, statusLine, 0x00000000)
     end
 end)
-pool.run()
+
+pool.run():next(function()
+    print("The pool finished running!!!")
+end):catch(function(error)
+    io.stderr:write(string.format("There was a problem running the pool: %s", error))
+    print(string.format("There was a problem running the pool: %s", error))
+end)
\ No newline at end of file
diff --git a/pool.lua b/pool.lua
index 0d59a64..50b2ba3 100644
--- a/pool.lua
+++ b/pool.lua
@@ -1,7 +1,17 @@
+local callback, set_timer_timeout = callback, set_timer_timeout
+
 local base = string.gsub(@@LUA_SCRIPT_FILENAME@@, "(.*[/\\])(.*)", "%1")
 
+local Promise = dofile(base.."/promise.lua")
+-- Only the parent should manage ticks!
+callback.register('timer', function()
+    Promise.update()
+	set_timer_timeout(1)
+end)
+set_timer_timeout(1)
+
 local config = dofile(base.."/config.lua")
-local util = dofile(base.."/util.lua")
+local util = dofile(base.."/util.lua")(Promise)
 local serpent = dofile(base.."/serpent.lua")
 local libDeflate = dofile(base.."/LibDeflate.lua")
 
@@ -386,15 +396,17 @@ local function addToSpecies(child)
 	end
 end
 
-local function initializePool(after)
-	pool = newPool()
+local function initializePool()
+	local promise = Promise.new()
+	promise:resolve()
+	return promise:next(function()
+		pool = newPool()
 
-	for i=1,config.NeatConfig.Population do
-		basic = basicGenome()
-		addToSpecies(basic)
-	end
-
-    after()
+		for i=1,config.NeatConfig.Population do
+			local basic = basicGenome()
+			addToSpecies(basic)
+		end
+	end)
 end
 
 local function bytes(x)
@@ -406,33 +418,40 @@ local function bytes(x)
 end
 
 local function writeFile(filename)
-    local file = io.open(filename, "w")
-    local dump = serpent.dump(pool)
-    local zlib = libDeflate:CompressDeflate(dump)
-    file:write("\x1f\x8b\x08\x00\x00\x00\x00\x00\x00\x00")
-    file:write(zlib)
-    file:write(string.char(0,0,0,0))
-    file:write(bytes(#dump % (2^32)))
-    file:close()
-    return
+	local promise = Promise.new()
+	promise:resolve()
+	return promise:next(function ()
+		local file = io.open(filename, "w")
+		local dump = serpent.dump(pool)
+		local zlib = libDeflate:CompressDeflate(dump)
+		file:write("\x1f\x8b\x08\x00\x00\x00\x00\x00\x00\x00")
+		file:write(zlib)
+		file:write(string.char(0,0,0,0))
+		file:write(bytes(#dump % (2^32)))
+		file:close()
+	end)
 end
 
--- FIXME Save/load mechanism has to be rethought with items running in parallel
-local function loadFile(filename, after)
-    message("Loading pool from " .. filename, 0x00999900)
-    local file = io.open(filename, "r")
-    if file == nil then
-        message("File could not be loaded", 0x00990000)
-        return
-    end
-    local contents = file:read("*all")
-    local ok, obj = serpent.load(libDeflate:DecompressDeflate(contents:sub(11, #contents - 8)))
-    if not ok then
-        message("Error parsing pool file", 0x00990000)
-        return
-    end
+-- FIXME This isn't technically asynchronous. Probably can't be though.
+local function loadFile(filename)
+	local promise = Promise.new()
+	promise:resolve()
+	return promise:next(function()
+		message("Loading pool from " .. filename, 0x00999900)
+		local file = io.open(filename, "r")
+		if file == nil then
+			message("File could not be loaded", 0x00990000)
+			return
+		end
+		local contents = file:read("*all")
+		local ok, obj = serpent.load(libDeflate:DecompressDeflate(contents:sub(11, #contents - 8)))
+		if not ok then
+			message("Error parsing pool file", 0x00990000)
+			return
+		end
 
-    pool = obj
+		pool = obj
+	end)
 end
 
 local function savePool()
@@ -441,9 +460,8 @@ local function savePool()
     message(string.format("Saved \"%s\"!", filename:sub(#filename - 50)), 0x00009900)
 end
 
-local function loadPool(after)
-	loadFile(_M.saveLoadFile, after)
-    after()
+local function loadPool()
+	return loadFile(_M.saveLoadFile)
 end
 
 local function processRenderForm(form)
@@ -471,7 +489,7 @@ end
 local function crossover(g1, g2)
 	-- Make sure g1 is the higher fitness genome
 	if g2.fitness > g1.fitness then
-		tempg = g1
+		local tempg = g1
 		g1 = g2
 		g2 = tempg
 	end
@@ -562,11 +580,11 @@ end
 local function breedChild(species)
 	local child = {}
 	if math.random() < config.NeatConfig.CrossoverChance then
-		g1 = species.genomes[math.random(1, #species.genomes)]
-		g2 = species.genomes[math.random(1, #species.genomes)]
+		local g1 = species.genomes[math.random(1, #species.genomes)]
+		local g2 = species.genomes[math.random(1, #species.genomes)]
 		child = crossover(g1, g2)
 	else
-		g = species.genomes[math.random(1, #species.genomes)]
+		local g = species.genomes[math.random(1, #species.genomes)]
 		child = copyGenome(g)
 	end
 	
@@ -605,7 +623,7 @@ local function removeWeakSpecies()
 	local sum = totalAverageFitness()
 	for s = 1,#pool.species do
 		local species = pool.species[s]
-		breed = math.floor(species.averageFitness / sum * config.NeatConfig.Population)
+		local breed = math.floor(species.averageFitness / sum * config.NeatConfig.Population)
 		if breed >= 1 then
 			table.insert(survived, species)
 		end
@@ -628,7 +646,7 @@ local function newGeneration()
 	local children = {}
 	for s = 1,#pool.species do
 		local species = pool.species[s]
-		breed = math.floor(species.averageFitness / sum * config.NeatConfig.Population) - 1
+		local breed = math.floor(species.averageFitness / sum * config.NeatConfig.Population) - 1
 		for i=1,breed do
 			table.insert(children, breedChild(species))
 		end
@@ -652,7 +670,7 @@ local function newGeneration()
 	writeFile(_M.saveLoadFile .. ".gen" .. pool.generation .. ".pool")
 end
 
-local runner = Runner()
+local runner = Runner(Promise)
 runner.onMessage(function(msg, color)
 	message(msg, color)
 end)
@@ -671,68 +689,72 @@ local topRequested = false
 
 local loadRequested = false
 local saveRequested = false
-local function mainLoop(currentSpecies)
-    if loadRequested then
-        loadRequested = false
-        loadPool(mainLoop)
-        return
-    end
+local function mainLoop(currentSpecies, topGenome)
+	if currentSpecies == nil then
+		currentSpecies = 1
+	end
 
-    if saveRequested then
-        saveRequested = false
-        savePool()
-    end
+	local slice = pool.species[currentSpecies]
+	local promise = Promise.new()
+	promise:resolve()
+	return promise:next(function()
+		if loadRequested then
+			loadRequested = false
+			currentSpecies = nil
+			-- FIXME
+			return loadPool()
+		end
 
-    if topRequested then
-        topRequested = false
-        playTop()
-        return
-    end
+		if saveRequested then
+			saveRequested = false
+			savePool()
+		end
 
-    if not config.Running then
-        -- FIXME Tick?
-    end
+		if topRequested then
+			topRequested = false
+			return playTop()
+		end
 
-    if currentSpecies == nil then
-        currentSpecies = 1
-    end
+		if not config.Running then
+			-- FIXME Tick?
+		end
 
-    local slice = pool.species[currentSpecies]
-    if hasThreads then
-        slice = {}
-        for i=currentSpecies, currentSpecies + config.NeatConfig.Threads - 1, 1 do
-            if pool.species[i] == nil then
-                break
-            end
+		if hasThreads then
+			slice = {}
+			for i=currentSpecies, currentSpecies + config.NeatConfig.Threads - 1, 1 do
+				if pool.species[i] == nil then
+					break
+				end
 
-            table.insert(slice, pool.species[i])
-        end
-    end
-    local finished = 0
-    runner.run(
-        slice, 
-        pool.generation, 
-        function()
-            -- Genome callback
-        end,
-        function()
-            if hasThreads then
-                finished = finished + 1
-                if finished ~= #slice then
-                    return
-                end
-                currentSpecies = currentSpecies + #slice
-            else
-                currentSpecies = currentSpecies + 1
-            end
+				table.insert(slice, pool.species[i])
+			end
+		end
+		local finished = 0
 
-            if currentSpecies > #pool.species then
-                newGeneration()
-                currentSpecies = 1
-            end
-            mainLoop(currentSpecies)
-        end
-    )
+		return runner.run(
+			slice,
+			pool.generation,
+			function()
+				-- Genome callback
+				-- FIXME Should we do something here??? What was your plan, past me?
+			end
+		):next(function()
+			if hasThreads then
+				currentSpecies = currentSpecies + #slice
+			else
+				currentSpecies = currentSpecies + 1
+			end
+
+			if currentSpecies > #pool.species then
+				newGeneration()
+				currentSpecies = 1
+			end
+		end)
+    end):next(function ()
+		if topGenome == nil then
+			return mainLoop(currentSpecies)
+		end
+	end)
 end
 
 playTop = function()
@@ -749,7 +771,7 @@ playTop = function()
 	end
 	
     -- FIXME genome
-    mainLoop(maxs)
+    return mainLoop(maxs, maxg)
 end
 
 function _M.requestLoad(filename)
@@ -775,15 +797,19 @@ function _M.requestTop()
 end
 
 function _M.run(reset)
+	local promise = nil
     if pool == nil or reset == true then
-        initializePool(function() 
-            writeFile(config.PoolDir.."temp.pool")
-            mainLoop()
-        end)
-    else
-        writeFile(config.PoolDir.."temp.pool")
-        mainLoop()
+        promise = initializePool()
+	else
+		promise = Promise.new()
+		promise:resolve()
     end
+
+	return promise:next(function()
+		return writeFile(config.PoolDir.."temp.pool")
+	end):next(function ()
+		return mainLoop()
+	end)
 end
 
 return _M
diff --git a/promise.lua b/promise.lua
index 8fd9c17..31943db 100644
--- a/promise.lua
+++ b/promise.lua
@@ -78,7 +78,6 @@ transition = function(promise, state, value)
   if promise.state == state
     or promise.state ~= State.PENDING
     or ( state ~= State.FULFILLED and state ~= State.REJECTED )
-    or value == nil
   then
     return
   end
diff --git a/runner-process.lua b/runner-process.lua
index cfd5a1a..420e360 100644
--- a/runner-process.lua
+++ b/runner-process.lua
@@ -1,18 +1,22 @@
-local gui, utime = gui, utime
+local gui, utime, callback, set_timer_timeout = gui, utime, callback, set_timer_timeout
 
 local base = string.gsub(@@LUA_SCRIPT_FILENAME@@, "(.*[/\\])(.*)", "%1")
 
 local Promise = dofile(base.."/promise.lua")
+-- Only the parent should manage ticks!
+callback.register('timer', function()
+    Promise.update()
+    set_timer_timeout(1)
+end)
+set_timer_timeout(1)
 
 local Runner = dofile(base.."/runner.lua")
 local serpent = dofile(base.."/serpent.lua")
-local util = dofile(base.."/util.lua")
+local util = dofile(base.."/util.lua")(Promise)
 
 local inputFilePath = os.getenv("RUNNER_INPUT_FILE")
 local outputFilePath = os.getenv("RUNNER_OUTPUT_FILE")
 
-local first = false
-
 local outContents = {}
 
 local statusLine = nil
@@ -22,7 +26,7 @@ local species = nil
 local speciesId = -1
 local generationIndex = nil
 
-local runner = Runner()
+local runner = Runner(Promise)
 runner.onMessage(function(msg, color)
     statusLine = msg
     statusColor = color
@@ -78,32 +82,7 @@ runner.onLoad(function(filename)
     )
 end)
 
-local waiter = nil
-if not util.isWin then
-    waiter = util.startWaiting(inputFilePath)
-end
-
 local function waitLoop()
-    if not first then
-        local sec, usec = utime()
-        local ts = sec * 1000000 + usec
-
-        local outFile = io.open(outputFilePath, "w")
-        outFile:write(serpent.dump({ type = 'onInit', ts = ts }))
-        outFile:close()
-
-        print(string.format('Wrote init to output at %d', ts))
-
-
-        first = true
-    end
-
-    print('Waiting for input from master process')
-
-    if not util.isWin then
-        util.finishWaiting(waiter)
-    end
-
     local inputData = nil
     local ok = false
     while not ok or inputData == nil or speciesId == inputData[1].id do
@@ -128,7 +107,7 @@ local function waitLoop()
 
     print('Running')
 
-    runner.run(
+    return runner.run(
         species,
         generationIndex,
         function(genome, index)
@@ -141,33 +120,55 @@ local function waitLoop()
                     speciesId = speciesId,
                 })
             )
-        end,
-        function()
-            table.insert(
-                outContents,
-                serpent.dump({
-                    type = 'onFinish',
-                    speciesId = speciesId,
-                })
-            )
-
-            -- Truncate the input file to reduce the amount of time
-            -- wasted if we reopen it too early
-            local inputFile = io.open(inputFilePath, "w")
-            inputFile:close()
-
-            if not util.isWin then
-                waiter = util.startWaiting(inputFilePath)
-            end
-
-            -- Write the result
-            local outFile = io.open(outputFilePath, "w")
-            outFile:write(table.concat(outContents, "\n"))
-            outFile:close()
-
-            waitLoop()
         end
-    )
+    ):next(function()
+        table.insert(
+            outContents,
+            serpent.dump({
+                type = 'onFinish',
+                speciesId = speciesId,
+            })
+        )
+
+        -- Truncate the input file to reduce the amount of time
+        -- wasted if we reopen it too early
+        local inputFile = io.open(inputFilePath, "w")
+        inputFile:close()
+
+        local waiter = nil
+        if util.isWin then
+            waiter = Promise.new()
+            waiter:resolve()
+        else
+            waiter = util.waitForFiles(inputFilePath)
+        end
+
+        -- Write the result
+        local outFile = io.open(outputFilePath, "w")
+        outFile:write(table.concat(outContents, "\n"))
+        outFile:close()
+
+        return waiter
+    end):next(waitLoop)
 end
 
-waitLoop()
\ No newline at end of file
+local waiter = nil
+if util.isWin then
+    waiter = Promise.new()
+    waiter:resolve()
+else
+    waiter = util.waitForFiles(inputFilePath)
+end
+
+local sec, usec = utime()
+local ts = sec * 1000000 + usec
+
+local outFile = io.open(outputFilePath, "w")
+outFile:write(serpent.dump({ type = 'onInit', ts = ts }))
+outFile:close()
+
+print(string.format('Wrote init to output at %d', ts))
+
+waiter:next(waitLoop):catch(function(error)
+    print('ERROR: '..error)
+end)
\ No newline at end of file
diff --git a/runner-wrapper.lua b/runner-wrapper.lua
index 8299d3c..6793c69 100644
--- a/runner-wrapper.lua
+++ b/runner-wrapper.lua
@@ -2,7 +2,9 @@ local random = random
 
 local base = string.gsub(@@LUA_SCRIPT_FILENAME@@, "(.*[/\\])(.*)", "%1")
 
-local util = dofile(base.."/util.lua")
+local Promise = nil
+
+local util = nil
 local config = dofile(base.."/config.lua")
 local serpent = dofile(base.."/serpent.lua")
 local temps = {
@@ -25,6 +27,9 @@ local tmpFileName = tempDir.."/donk_runner_"..
     string.hex(math.floor(random.integer(0, 0xffffffff)))..
     string.hex(math.floor(random.integer(0, 0xffffffff)))
 
+local inputPrefix = tmpFileName..'_input_'
+local outputPrefix = tmpFileName..'_output_'
+
 local function message(_M, msg, color)
     if color == nil then
         color = 0x00009900
@@ -59,7 +64,46 @@ local function onMessage(_M, handler)
     table.insert(_M.onMessageHandler, handler)
 end
 
-return function()
+--- Launches the child processes
+---@param _M table The instance
+---@param count integer Number of processes needed
+---@return Promise Promise A promise that resolves when all the processes are ready
+local function launchChildren(_M, count)
+    local children = {}
+    while #_M.poppets < count do
+        local i = #_M.poppets+1
+        local outputFileName = outputPrefix..i
+        local inputFileName = inputPrefix..i
+
+        local settingsDir = nil
+        if util.isWin then
+            settingsDir = tempDir.."/donk_runner_settings_"..i
+            util.mkdir(settingsDir)
+        end
+
+        local envs = {
+            RUNNER_INPUT_FILE = inputFileName,
+            RUNNER_OUTPUT_FILE = outputFileName,
+            APPDATA = settingsDir,
+        }
+
+        local child = util.waitForFiles(outputFileName)
+
+        local cmd = '"'.._M.hostProcess..'" "--rom='..config.ROM..'" --unpause "--lua='..base..'/runner-process.lua"'
+        local poppet = util.popenCmd(cmd, nil, envs)
+        table.insert(_M.poppets, poppet)
+
+        table.insert(children, child)
+    end
+
+    return Promise.all(table.unpack(children))
+end
+
+return function(promise)
+    -- FIXME Should this be a global???
+    Promise = promise
+    util = dofile(base.."/util.lua")(Promise)
+    -- FIXME Maybe don't do this in the "constructor"?
     if util.isWin then
         util.downloadFile('https://github.com/watchexec/watchexec/releases/download/1.13.1/watchexec-1.13.1-x86_64-pc-windows-gnu.zip', base..'/watchexec.zip')
         util.unzip(base..'/watchexec.zip', base)
@@ -102,111 +146,91 @@ return function()
         onLoad(_M, handler)
     end
 
-    _M.run = function(species, generationIdx, genomeCallback, finishCallback)
-        local inputPrefix = tmpFileName..'_input_'
-        local outputPrefix = tmpFileName..'_output_'
-        
-        -- Create the input files and output files
-        for i=1,#species,1 do
-            local inputFileName = inputPrefix..i
-            local inputFile = io.open(inputFileName, 'a')
-            inputFile:close()
+    _M.run = function(speciesSlice, generationIdx, genomeCallback)
+        local promise = Promise.new()
+        promise:resolve()
+        return promise:next(function()
+            -- Create the input files and output files
+            for i=1,#speciesSlice,1 do
+                local inputFileName = inputPrefix..i
+                local inputFile = io.open(inputFileName, 'a')
+                inputFile:close()
 
-            local outputFileName = outputPrefix..i
-            local outputFile = io.open(outputFileName, 'a')
-            outputFile:close()
-        end
-
-        while #_M.poppets < #species do
-            local i = #_M.poppets+1
-            local outputFileName = outputPrefix..i
-            local inputFileName = inputPrefix..i
-
-            message(_M, _M.hostProcess)
-
-            local settingsDir = nil
-            if isWin then
-                settingsDir = tempDir.."/donk_runner_settings_"..i
-                util.mkdir(settingsDir)
+                local outputFileName = outputPrefix..i
+                local outputFile = io.open(outputFileName, 'a')
+                outputFile:close()
             end
 
-            local envs = {
-                RUNNER_INPUT_FILE = inputFileName,
-                RUNNER_OUTPUT_FILE = outputFileName,
-                APPDATA = settingsDir,
-            }
+            return launchChildren(_M, #speciesSlice)
+        end):next(function()
+            local outputFileNames = {}
+            for i=1,#speciesSlice,1 do
+                table.insert(outputFileNames, outputPrefix..i)
+            end
 
-            local waiter = util.startWaiting(outputFileName)
+            local waiter = util.waitForFiles(outputFileNames, nil, tmpFileName.."_output_*")
 
-            local cmd = '"'.._M.hostProcess..'" "--rom='..config.ROM..'" --unpause "--lua='..base..'/runner-process.lua"'
-            local poppet = util.popenCmd(cmd, nil, envs)
-            table.insert(_M.poppets, poppet)
+            message(_M, 'Setting up child processes')
 
-            util.finishWaiting(waiter)
-        end
+            for i=1,#speciesSlice,1 do
 
-        local waiters = {}
-        for i=1,#species,1 do
-            table.insert(waiters, outputPrefix..i)
-        end
+                local inputFileName = tmpFileName.."_input_"..i
+                local inputFile = io.open(inputFileName, 'w')
+                inputFile:write(serpent.dump({speciesSlice[i], generationIdx}))
+                inputFile:close()
+            end
 
-        local waiter = util.startWaiting(waiters, nil, tmpFileName.."_output_*")
+            message(_M, 'Waiting for child processes to finish')
 
-        message(_M, 'Setting up child processes')
+            return waiter
+        end):next(function()
+            message(_M, 'Child processes finished')
 
-        for i=1,#species,1 do
+            local finished = 0
+            for i=1,#speciesSlice,1 do
+                message(_M, "Processing output "..i)
+                local outputFileName = tmpFileName..'_output_'..i
+                local outputFile = io.open(outputFileName, "r")
+                local line = ""
+                repeat
+                    local ok, obj = serpent.load(line)
+                    if not ok then
+                        goto continue
+                    end
 
-            local inputFileName = tmpFileName.."_input_"..i
-            local inputFile = io.open(inputFileName, 'w')
-            inputFile:write(serpent.dump({species[i], generationIdx}))
-            inputFile:close()
-        end
+                    if obj == nil then
+                        goto continue
+                    end
 
-        message(_M, 'Waiting for child processes to finish')
-
-        util.finishWaiting(waiter, #waiters)
-
-        message(_M, 'Child processes finished')
-
-        for i=1,#species,1 do
-            message(_M, "Processing output "..i)
-            local outputFileName = tmpFileName..'_output_'..i
-            local outputFile = io.open(outputFileName, "r")
-            local line = ""
-            repeat
-                local ok, obj = serpent.load(line)
-                if not ok then
-                    goto continue
-                end
-
-                if obj == nil then
-                    goto continue
-                end
-
-                if obj.type == 'onMessage' then
-                    message(_M, obj.msg, obj.color)
-                elseif obj.type == 'onLoad' then
-                    load(_M, obj.filename)
-                elseif obj.type == 'onSave' then
-                    save(_M, obj.filename)
-                elseif obj.type == 'onGenome' then
-                    for i=1,#species,1 do
-                        local s = species[i]
-                        if s.id == obj.speciesId then
-                            s.genomes[obj.genomeIndex] = obj.genome
-                            break
+                    if obj.type == 'onMessage' then
+                        message(_M, obj.msg, obj.color)
+                    elseif obj.type == 'onLoad' then
+                        load(_M, obj.filename)
+                    elseif obj.type == 'onSave' then
+                        save(_M, obj.filename)
+                    elseif obj.type == 'onGenome' then
+                        for i=1,#speciesSlice,1 do
+                            local s = speciesSlice[i]
+                            if s.id == obj.speciesId then
+                                s.genomes[obj.genomeIndex] = obj.genome
+                                break
+                            end
+                        end
+                        genomeCallback(obj.genome, obj.index)
+                    elseif obj.type == 'onFinish' then
+                        finished = finished + 1
+                        if finished == #speciesSlice then
+                            outputFile:close()
+                            return
                         end
                     end
-                    genomeCallback(obj.genome, obj.index)
-                elseif obj.type == 'onFinish' then
-                    finishCallback()
-                end
 
-                ::continue::
-                line = outputFile:read()
-            until(line == "" or line == nil)
-            outputFile:close()
-        end
+                    ::continue::
+                    line = outputFile:read()
+                until(line == "" or line == nil)
+            end
+            error(string.format("Some processes never finished? Saw %d terminations.", finished))
+        end)
     end
 
     return _M
diff --git a/runner.lua b/runner.lua
index 9ea2bd1..52d51f4 100644
--- a/runner.lua
+++ b/runner.lua
@@ -12,6 +12,8 @@ local Outputs = #config.ButtonNames
 local guiWidth = 0 
 local guiHeight = 0
 
+local Promise = nil
+
 local function message(_M, msg, color)
     if color == nil then
         color = 0x00009900
@@ -213,19 +215,21 @@ local function displayGenome(genome)
     gui.renderctx.setnull()
 end
 
-local function advanceFrame(_M, after)
-    table.insert(_M.onFrameAdvancedHandler, after)
+local function advanceFrame(_M)
+    local promise = Promise.new()
+    table.insert(_M.onFrameAdvancedHandler, promise)
+    return promise
 end
 
 local function processFrameAdvanced(_M)
     for i=#_M.onFrameAdvancedHandler,1,-1 do
-        table.remove(_M.onFrameAdvancedHandler, i)()
+        table.remove(_M.onFrameAdvancedHandler, i):resolve()
     end
 end
 
 local buttons = nil
 local buttonCtx = gui.renderctx.new(500, 70)
-function displayButtons()
+local function displayButtons(_M)
     buttonCtx:set()
     buttonCtx:clear()
 
@@ -249,7 +253,7 @@ function displayButtons()
 
     local insert = ""
     local confirm = "[Tab] Type in filename"
-    if inputmode then
+    if _M.inputmode then
         insert = "_"
         confirm = "[Tab] Confirm filename"
     end
@@ -264,7 +268,7 @@ end
 
 local formCtx = nil
 local form = nil
-function displayForm(_M)
+local function displayForm(_M)
     if #_M.onRenderFormHandler == 0 then
         return
     end
@@ -303,7 +307,7 @@ function displayForm(_M)
 	gui.text(320, 65, string.format("Current Area: %04x", _M.currentArea))
 	gui.text(320, 80, "Rightmost: "..rightmost)
 
-    displayButtons()
+    displayButtons(_M)
     formCtx:set()
     buttons:draw(5, 130)
 
@@ -373,11 +377,12 @@ local function evaluateNetwork(_M, network, inputs, inputDeltas)
 	return outputs
 end
 
+local controller = nil
 local function evaluateCurrent(_M)
 	local genome = _M.currentSpecies.genomes[_M.currentGenomeIndex]
 	
 	local inputDeltas = {}
-	inputs, inputDeltas = game.getInputs()
+	local inputs, inputDeltas = game.getInputs()
 
 	controller = evaluateNetwork(_M, genome.network, inputs, inputDeltas)
 
@@ -405,9 +410,70 @@ local function fitnessAlreadyMeasured(_M)
 	return genome.fitness ~= 0
 end
 
+local rewinds = {}
 local rew = movie.to_rewind(config.NeatConfig.Filename)
+local function rewind()
+    local promise = Promise.new()
+    movie.unsafe_rewind(rew)
+    table.insert(rewinds, promise)
+    return promise
+end
 
-local function initializeRun(_M, after)
+local function rewound()
+    for i=#rewinds,1,-1 do
+        local promise = table.remove(rewinds, i)
+        promise:resolve()
+    end
+end
+
+local function newNeuron()
+	local neuron = {}
+	neuron.incoming = {}
+	neuron.value = 0.0
+	--neuron.dw = 1
+	return neuron
+end
+
+local function generateNetwork(genome)
+	local network = {}
+	network.neurons = {}
+	
+	for i=1,Inputs do
+		network.neurons[i] = newNeuron()
+	end
+	
+	for o=1,Outputs do
+        if o == 4 then
+            goto continue
+        end
+
+        network.neurons[config.NeatConfig.MaxNodes+o] = newNeuron()
+
+        ::continue::
+	end
+	
+	table.sort(genome.genes, function (a,b)
+		return (a.out < b.out)
+	end)
+	for i=1,#genome.genes do
+		local gene = genome.genes[i]
+		if gene.enabled then
+			if network.neurons[gene.out] == nil then
+				network.neurons[gene.out] = newNeuron()
+			end
+			local neuron = network.neurons[gene.out]
+			table.insert(neuron.incoming, gene)
+			if network.neurons[gene.into] == nil then
+				network.neurons[gene.into] = newNeuron()
+			end
+		end
+	end
+
+	genome.network = network
+end
+
+
+local function initializeRun(_M)
     message(_M, string.format("Total Genomes: %d", #_M.currentSpecies.genomes))
 
     settings.set_speed("turbo")
@@ -419,12 +485,46 @@ local function initializeRun(_M, after)
     end
     exec('enable-sound '..enableSound)
     gui.subframe_update(false)
-    table.insert(_M.runInitialized, after)
-    movie.unsafe_rewind(rew)
+
+    return rewind():next(function()
+        if config.StartPowerup ~= nil then
+            game.writePowerup(config.StartPowerup)
+        end
+        _M.currentFrame = 0
+        _M.timeout = config.NeatConfig.TimeoutConstant
+        -- Kill the run if we go back to the map screen
+        game.onceMapLoaded(function()
+            _M.timeout = -100000
+        end)
+        _M.bumps = 0
+        -- Penalize player for collisions that do not result in enemy deaths
+        game.onEmptyHit(function()
+            _M.bumps = _M.bumps + 1
+        end)
+        game.clearJoypad()
+        _M.startKong = game.getKong()
+        _M.startBananas = game.getBananas()
+        _M.startKrem = game.getKremCoins()
+        _M.lastKrem = _M.startKrem
+        _M.startCoins = game.getCoins()
+        _M.startLives = game.getLives()
+        _M.partyHitCounter = 0
+        _M.powerUpCounter = 0
+        _M.powerUpBefore = game.getBoth()
+        _M.currentArea = game.getCurrentArea()
+        _M.lastArea = _M.currentArea
+        _M.rightmost = { [_M.currentArea] = 0 }
+        _M.upmost = { [_M.currentArea] = 0 }
+        local genome = _M.currentSpecies.genomes[_M.currentGenomeIndex]
+        generateNetwork(genome)
+        evaluateCurrent(_M)
+    end)
 end
 
+local frame = 0
+
 local function mainLoop(_M, genome)
-    advanceFrame(_M, function()
+    return advanceFrame(_M):next(function()
         if genome ~= nil then
             _M.currentFrame = _M.currentFrame + 1
         end
@@ -432,11 +532,7 @@ local function mainLoop(_M, genome)
         genome = _M.currentSpecies.genomes[_M.currentGenomeIndex]
 
         if _M.drawFrame % 10 == 0 then
-            --if not pcall(function()
-                displayGenome(genome)
-            --end) then
-            --message(_M, "Could not render genome graph", 0x00990000)
-            --end
+            displayGenome(genome)
         end
         
         if _M.currentFrame%5 == 0 then
@@ -529,8 +625,7 @@ local function mainLoop(_M, genome)
         -- Continue if we haven't timed out
         local timeoutBonus = _M.currentFrame / 4
         if _M.timeout + timeoutBonus > 0 then
-            mainLoop(_M, genome)
-            return
+            return mainLoop(_M, genome)
         end
         
         -- Timeout calculations beyond this point
@@ -609,103 +704,16 @@ local function mainLoop(_M, genome)
                 input.keyhook("9", false)
                 input.keyhook("tab", false)
 
-                _M.finishCallback()
                 return
             end
         end
-        initializeRun(_M, function() 
-            mainLoop(_M, genome)
+
+        return initializeRun(_M):next(function()
+            return mainLoop(_M, genome)
         end)
     end)
 end
 
-local function newNeuron()
-	local neuron = {}
-	neuron.incoming = {}
-	neuron.value = 0.0
-	--neuron.dw = 1
-	return neuron
-end
-
-local function generateNetwork(genome)
-	local network = {}
-	network.neurons = {}
-	
-	for i=1,Inputs do
-		network.neurons[i] = newNeuron()
-	end
-	
-	for o=1,Outputs do
-        if o == 4 then
-            goto continue
-        end
-
-        network.neurons[config.NeatConfig.MaxNodes+o] = newNeuron()
-
-        ::continue::
-	end
-	
-	table.sort(genome.genes, function (a,b)
-		return (a.out < b.out)
-	end)
-	for i=1,#genome.genes do
-		local gene = genome.genes[i]
-		if gene.enabled then
-			if network.neurons[gene.out] == nil then
-				network.neurons[gene.out] = newNeuron()
-			end
-			local neuron = network.neurons[gene.out]
-			table.insert(neuron.incoming, gene)
-			if network.neurons[gene.into] == nil then
-				network.neurons[gene.into] = newNeuron()
-			end
-		end
-	end
-
-	genome.network = network
-end
-
-local function elapsed(_M)
-    if config.StartPowerup ~= nil then
-        game.writePowerup(config.StartPowerup)
-    end
-    _M.currentFrame = 0
-    _M.timeout = config.NeatConfig.TimeoutConstant
-    -- Kill the run if we go back to the map screen
-    game.onceMapLoaded(function()
-        _M.timeout = -100000
-    end)
-    _M.bumps = 0
-    -- Penalize player for collisions that do not result in enemy deaths
-    game.onEmptyHit(function()
-        _M.bumps = _M.bumps + 1
-    end)
-    game.clearJoypad()
-    _M.startKong = game.getKong()
-    _M.startBananas = game.getBananas()
-    _M.startKrem = game.getKremCoins()
-    _M.lastKrem = _M.startKrem
-    _M.startCoins = game.getCoins()
-    _M.startLives = game.getLives()
-    _M.partyHitCounter = 0
-    _M.powerUpCounter = 0
-    _M.powerUpBefore = game.getBoth()
-    _M.currentArea = game.getCurrentArea()
-    _M.lastArea = _M.currentArea
-    _M.rightmost = { [_M.currentArea] = 0 }
-    _M.upmost = { [_M.currentArea] = 0 }
-    local genome = _M.currentSpecies.genomes[_M.currentGenomeIndex]
-    generateNetwork(genome)
-    evaluateCurrent(_M)
-    for i=#_M.runInitialized,1,-1 do
-        table.remove(_M.runInitialized, i)()
-    end
-end
-
-local function rewound()
-    set_timer_timeout(1)
-end
-
 local function register(_M, name, func)
     callback.register(name, func)
     _M.dereg[#_M.dereg+1] = { name, func }
@@ -740,7 +748,7 @@ local function keyhook (_M, key, state)
         if key == "tab" then
             _M.inputmode = not _M.inputmode
             _M.helddown = key
-        elseif inputmode then
+        elseif _M.inputmode then
             return
         elseif key == "1" then
             _M.helddown = key
@@ -761,13 +769,13 @@ local function keyhook (_M, key, state)
             pool.run(true)
         end
     elseif state.value == 0 then
-        helddown = nil
+        _M.helddown = nil
     end
 end
 
 local function saveLoadInput(_M)
     local inputs = input.raw()
-    if not inputmode then
+    if not _M.inputmode then
         -- FIXME
         _M.saveLoadFile = config.NeatConfig.SaveFile
         return
@@ -829,30 +837,25 @@ local function saveLoadInput(_M)
     end
 end
 
-local function run(_M, species, generationIdx, genomeCallback, finishCallback)
+local function run(_M, species, generationIdx, genomeCallback)
     game.registerHandlers()
 
     _M.currentGenerationIndex = generationIdx
     _M.currentSpecies = species
     _M.currentGenomeIndex = 1
     _M.genomeCallback = genomeCallback
-    _M.finishCallback = finishCallback
     register(_M, 'paint', function()
         painting(_M)
     end)
     register(_M, 'input', function()
+        frame = frame + 1
         processFrameAdvanced(_M)
-    end)
-    register(_M, 'input', function()
         saveLoadInput(_M)
     end)
     register(_M, 'keyhook', function(key, state)
         keyhook(_M, key, state)
     end)
     register(_M, 'post_rewind', rewound)
-    register(_M, 'timer', function()
-        elapsed(_M)
-    end)
 
     input.keyhook("1", true)
     input.keyhook("4", true)
@@ -861,8 +864,8 @@ local function run(_M, species, generationIdx, genomeCallback, finishCallback)
     input.keyhook("9", true)
     input.keyhook("tab", true)
 
-    initializeRun(_M, function()
-        mainLoop(_M)
+    return initializeRun(_M):next(function()
+        return mainLoop(_M)
     end)
 end
 
@@ -874,11 +877,11 @@ local function onRenderForm(_M, handler)
     table.insert(_M.onRenderFormHandler, handler)
 end
 
-return function()
+return function(promise)
+    Promise = promise
     local _M = {
         currentGenerationIndex = 1,
         currentSpecies = nil,
-        finishCallback = nil,
         genomeCallback = nil,
         currentGenomeIndex = 1,
         currentFrame = 0,
@@ -907,8 +910,6 @@ return function()
         upmost = {},
         lastBoth = 0,
 
-        runInitialized = {},
-
         onMessageHandler = {},
         onSaveHandler = {},
         onLoadHandler = {},
@@ -933,8 +934,8 @@ return function()
         onLoad(_M, handler)
     end
 
-    _M.run = function(species, generationIdx, genomeCallback, finishCallback)
-        run(_M, species, generationIdx, genomeCallback, finishCallback)
+    _M.run = function(species, generationIdx, genomeCallback)
+        return run(_M, species, generationIdx, genomeCallback)
     end
 
     return _M
diff --git a/tools/bsnes-launcher.lua b/tools/bsnes-launcher.lua
index d7feace..6fe849e 100644
--- a/tools/bsnes-launcher.lua
+++ b/tools/bsnes-launcher.lua
@@ -1,6 +1,6 @@
 local base = string.gsub(@@LUA_SCRIPT_FILENAME@@, "(.*[/\\])(.*)", "%1").."/.."
 
-local util = dofile(base.."/util.lua")
+local util = dofile(base.."/util.lua")()
 local config = dofile(base.."/config.lua")
 local mem = dofile(base.."/mem.lua")
 
diff --git a/tools/status-overlay.lua b/tools/status-overlay.lua
index 817d0a6..aa4e221 100644
--- a/tools/status-overlay.lua
+++ b/tools/status-overlay.lua
@@ -6,7 +6,7 @@ local warn = '========== The ROM must be running before running this script'
 io.stderr:write(warn)
 print(warn)
 
-local util = dofile(base.."/util.lua")
+local util = dofile(base.."/util.lua")()
 local mem = dofile(base.."/mem.lua")
 local spritelist = dofile(base.."/spritelist.lua")
 local game = dofile(base.."/game.lua")
@@ -436,3 +436,17 @@ input.keyhook("9", true)
 input.keyhook("0", true)
 
 set_timer_timeout(100 * 1000)
+
+for i=0,22,1 do
+    memory2.BUS:registerwrite(mem.addr.spriteBase + mem.size.sprite * i + mem.offset.sprite.x, function(addr, val)
+        print(memory.getregister('pc'))
+    end)
+end
+
+-- fe0a58 crate: near bunch and klomp on barrels
+-- fe0a58: Crate X position
+-- fe0a60: Crate Y position
+
+-- fe0a70 bunch: near crate and klomp on barrels
+-- fe0a70: X position
+-- fe0a72: Y position
\ No newline at end of file
diff --git a/util.lua b/util.lua
index e74c2fd..1dd4b96 100644
--- a/util.lua
+++ b/util.lua
@@ -2,6 +2,8 @@ local utime = utime
 
 local base = string.gsub(@@LUA_SCRIPT_FILENAME@@, "(.*[/\\])(.*)", "%1")
 
+local Promise = nil
+
 local _M = {}
 
 _M.isWin = package.config:sub(1, 1) == '\\'
@@ -102,27 +104,10 @@ function _M.closeCmd(handle)
     end
 end
 
-function _M.finishWaiting(waiter, count)
-    if count == nil then
-        count = 1
-    end
+function _M.waitForFiles(filenames, count, wild)
+    local promise = Promise.new()
+    promise:resolve()
 
-    if _M.isWin then
-        local i = 1
-        while i <= count do
-            local line = waiter:read("*l")
-            for chr in line:gmatch(";") do
-                i = i + 1
-            end
-            i = i + 1
-        end
-    else
-        waiter:read("*a")
-        _M.closeCmd(waiter)
-    end
-end
-
-function _M.startWaiting(filenames, count, wild)
     if type(filenames) == 'string' then
         if wild == nil then
             wild = filenames
@@ -135,16 +120,15 @@ function _M.startWaiting(filenames, count, wild)
         count = #filenames
     end
 
+    local poppet = nil
     if _M.isWin then
         local sec, usec = utime()
         print(string.format('Starting watching file at %d', sec * 1000000 + usec))
 
         local cmd = '"'..base..'/watchexec/watchexec.exe" "-w" "'..table.concat(filenames, '" "-w" "')..'" "echo" "%WATCHEXEC_WRITTEN_PATH%"'
-        local poppet = _M.popenCmd(cmd, base)
+        poppet = _M.popenCmd(cmd, base)
 
         poppet:read("*l")
-
-        return poppet
     else
         local watchCmd = ''
         if count == 1 then
@@ -167,8 +151,24 @@ done ) &
 wait
 EOF]]
         end
-        return _M.popenCmd(watchCmd)
+        poppet = _M.popenCmd(watchCmd)
     end
+
+    return promise:next(function()
+        if _M.isWin then
+            local i = 1
+            while i <= count do
+                local line = poppet:read("*l")
+                for chr in line:gmatch(";") do
+                    i = i + 1
+                end
+                i = i + 1
+            end
+        else
+            print(poppet:read("*a"))
+            _M.closeCmd(poppet)
+        end
+    end)
 end
 
 function _M.table_to_string(tbl)
@@ -214,4 +214,7 @@ function _M.file_exists(name)
    if f~=nil then io.close(f) return true else return false end
 end
 
-return _M
+return function(promise)
+    Promise = promise
+    return _M
+end
\ No newline at end of file