MissileCanyon For OpenOS (credit to SALDOR010)

local component = require("component")
local event = require("event")
local gpu = component.gpu
local computer = require("computer")

local oldPull = event.pull
event.pull = function(...) return oldPull(...) end

local args = {...}
local tdifficulty = 2

if args[1] then
    tdifficulty = args[1]
end

local wD, hT = gpu.getResolution()
hT = hT - 2

local difficulty = tonumber(tdifficulty) -- 1 = Easy, 2 = Mid, 3 = Hard
if difficulty ~= 1 and difficulty ~= 2 and difficulty ~= 3 then
    difficulty = 2
end

local points = {left = 0, right = 0, win = 10}
local gameBoard = {}
local msg = ""
local someoneWasDelayed = 0

-- Define colors for OpenComputers
local colors = {
    red = 0xFF0000, blue = 0x0000FF, white = 0xFFFFFF, black = 0x000000,
    pink = 0xFFC0CB, lightBlue = 0xADD8E6, orange = 0xFFA500, gray = 0x808080,
    yellow = 0xFFFF00, lime = 0x00FF00
}

for i = 1, wD do
    gameBoard[i] = {}
    for j = 1, hT do
        gameBoard[i][j] = nil
    end
end

for i = 1, hT do
    gameBoard[math.floor((wD/2)-5)][i] = {
        ["char"] = "@",
        ["charColor"] = colors.red,
        ["bgColor"] = colors.pink
    }
    gameBoard[math.floor((wD/2)+5)][i] = {
        ["char"] = "@",
        ["charColor"] = colors.blue,
        ["bgColor"] = colors.lightBlue
    }
end

local function drawGameBoard()
    for k, v in pairs(gameBoard) do
        for p, b in pairs(v) do
            if b ~= nil then
                if b["bgColor"] then
                    gpu.setBackground(b["bgColor"])
                    gpu.fill(k, p+1, 1, 1, " ")
                else
                    gpu.setBackground(colors.black)
                    gpu.fill(k, p, 1, 1, " ")
                end
                gpu.setForeground(b["charColor"])
                gpu.set(k, p+1, b["char"])
            end
        end
    end
end

local function updateGameBoard()
    local updatedBoard = {}
    for k, v in pairs(gameBoard) do
        updatedBoard[k] = {}
        for p, b in pairs(v) do
            updatedBoard[k][p] = b
        end
    end

    for k, v in pairs(gameBoard) do
        for p, b in pairs(v) do
            if b ~= nil then
                if b.velocity then
                    local newPos = k + b.velocity
                    if newPos > wD or newPos <= 0 then
                        if newPos > wD then points.left = points.left + 1 end
                        if newPos <= 0 then points.right = points.right + 1 end
                        updatedBoard[k][p] = nil
                    else
                        if updatedBoard[newPos][p] ~= nil then
                            local collided = updatedBoard[newPos][p]
                            if collided.explosion == nil and updatedBoard[k][p].explosion ~= true and updatedBoard[newPos][p].onCollision == nil then
                                for i = 1, 3 do
                                    for j = 1, 3 do
                                        local charChoices = {"@", "#", "*"}
                                        local colorChoices = {colors.red, colors.orange, colors.yellow}
                                        local charChoice = charChoices[math.random(1, 3)]
                                        local colorChoice = colorChoices[math.random(1, 3)]
                                        if newPos+i-2 <= wD and p+j-2 > 0 then
                                            if updatedBoard[newPos+i-2] then
                                                updatedBoard[newPos+i-2][p+j-2] = {
                                                    ["char"] = charChoice,
                                                    ["charColor"] = colors.white,
                                                    ["bgColor"] = colorChoice,
                                                    ["explosion"] = 6 + (math.random(-1, 2))
                                                }
                                            end
                                        end
                                    end
                                end
                            else
                                if updatedBoard[newPos][p].onCollision then
                                    updatedBoard[newPos][p].onCollision(gameBoard[k][p])
                                end
                                updatedBoard[k][p] = nil
                                updatedBoard[newPos][p] = nil
                            end
                        else
                            updatedBoard[newPos][p] = updatedBoard[k][p]
                            local colorChoices = {colors.orange, colors.gray, colors.red}
                            updatedBoard[k][p] = {
                                ["char"] = "@",
                                ["charColor"] = colorChoices[math.random(1, 3)],
                                ["bgColor"] = nil,
                                ["explosion"] = math.random(2, 3)
                            }
                        end
                    end
                end
                if b.explosion then
                    b.explosion = b.explosion - 1
                    if b.explosion <= 0 then
                        updatedBoard[k][p] = nil
                    end
                end
            end
        end
    end

    gameBoard = updatedBoard
    gpu.setBackground(colors.black)
    gpu.fill(1, 1, wD, hT+2, " ")
    drawGameBoard()
    gpu.setBackground(colors.gray)
    gpu.fill(1, hT+2, wD, 1, " ")
    gpu.fill(1, 1, wD, 1, " ")
    gpu.setForeground(colors.white)
    gpu.set(1, hT+2, msg)
    gpu.setForeground(colors.blue)
    gpu.set(1, 1, tostring(points.left))
    gpu.setForeground(colors.red)
    gpu.set(wD - #tostring(points.right), 1, tostring(points.right))

    if points.left >= points.win then
        gpu.setBackground(colors.black)
        gpu.fill(1, 1, wD, hT+2, " ")
        gpu.setForeground(colors.lightBlue)
        gpu.set(1, 1, "The player has won!")
        os.exit()
    elseif points.right >= points.win then
        gpu.setBackground(colors.black)
        gpu.fill(1, 1, wD, hT+2, " ")
        gpu.setForeground(colors.red)
        gpu.set(1, 1, "The AI has won!")
        os.exit()
    end
end

local playerWait = 0

local function spawnMissile(y, v, plr)
    local x = 0
    local charChoice = "<"
    if v <= -1 then
        x = wD
        charChoice = "<"
    elseif v >= 1 then
        x = 1
        charChoice = ">"
    end
    gameBoard[x][y] = {
        ["char"] = charChoice,
        ["charColor"] = colors.white,
        ["velocity"] = v
    }
    if plr then
        playerWait = 0.5
    end
end

local function scanForMissiles(enemy)
    local missiles = {}
    for k, v in pairs(gameBoard) do
        for p, b in pairs(v) do
            if enemy and b.char == ">" then
                missiles[#missiles+1] = {
                    ["x"] = k,
                    ["y"] = p
                }
            elseif enemy == false and b.char == "<" then
                missiles[#missiles+1] = {
                    ["x"] = k,
                    ["y"] = p
                }
            end
        end
    end
    return missiles
end

local AIWait = 0

local function AIUpdate()
    local missiles = scanForMissiles(true)
    local counterMissiles = scanForMissiles(false)
    local enemyMissile = false
    for k, v in pairs(missiles) do
        local notice = math.random(1, 5-difficulty)
        if notice == 1 then
            local found = false
            for p, b in pairs(counterMissiles) do
                if b.y == v.y then
                    found = true
                end
            end
            if not found then
                enemyMissile = true
                computer.pushSignal("fireMissile", v.y)
            end
        end
    end
    if not enemyMissile and difficulty >= 2 then
        local chance = math.random(1, 30/difficulty)
        if chance == 1 then
            computer.pushSignal("fireMissile", math.random(1, hT))
        end
    end
end

local function powerUp()
    local chance = math.random(1, 200)
    if chance == 7 then
        msg = "A bonus box has spawned!"
        local X = math.random(math.floor(wD/2)-4, math.floor(wD/2)+4)
        local Y = math.random(math.floor(hT/2)-4, math.floor(hT/2)+4)
        gameBoard[X][Y] = {
            ["char"] = "$",
            ["charColor"] = colors.white,
            ["bgColor"] = colors.lime,
            ["onCollision"] = function(collided)
                if someoneWasDelayed == 0 then
                    if collided.char == "<" then
                        playerWait = 3
                        someoneWasDelayed = 1
                    elseif collided.char == ">" then
                        AIWait = 3
                        someoneWasDelayed = 2
                    end
                end
            end
        }
    end
end

local function main()
    while true do
        local startTime = computer.uptime()
        powerUp()
        AIWait = AIWait - 0.1
        playerWait = playerWait - 0.1
        msg = tostring(someoneWasDelayed)
        if playerWait > 0 and someoneWasDelayed == 1 then
            msg = "You cannot fire a missile for "..playerWait.." seconds!"
        elseif playerWait <= 0 and someoneWasDelayed == 1 then
            msg = ""
            someoneWasDelayed = 0
        end
        if AIWait > 0 and someoneWasDelayed == 2 then
            msg = "The AI cannot fire a missile for "..AIWait.." seconds!"
        elseif AIWait <= 0 and someoneWasDelayed == 2 then
            someoneWasDelayed = 0
        end

        AIUpdate()
        updateGameBoard()

        local e = {event.pull(0)}
        if e[1] == "touch" then
            local _, _, x, y = table.unpack(e)
            y = y - 1
            if y > hT then y = hT end
            if x == 1 and playerWait <= 0 then
                spawnMissile(y, 1, true)
            end
        elseif e[1] == "fireMissile" then
            if AIWait <= 0 then
                local y = e[2]
                if y > hT then y = hT end
                spawnMissile(y, -1)
                AIWait = ({0.8, 0.6, 0.5})[tdifficulty] or 0.6
            end
        elseif e[1] == "interrupted" then
            gpu.setBackground(colors.black)
            gpu.fill(1, 1, wD, hT+2, " ")
            gpu.setForeground(colors.white)
            gpu.set(1, 1, "Aw, you quit the game early..")
            gpu.set(1, 2, "Oh well, thanks for playing!")
            break
        end

        local endTime = computer.uptime()
        local sleepTime = 0.1 - (endTime - startTime)
        if sleepTime > 0 then os.sleep(sleepTime) end
    end
end

main()