diff --git a/asteroids/main.lua b/asteroids/main.lua
new file mode 100644
index 0000000..3003812
--- /dev/null
+++ b/asteroids/main.lua
@@ -0,0 +1,196 @@
+local love = require("love")
+
+local function initGame()
+    return {
+        width = 800,
+        height = 600,
+        ship = {
+            radius = 30,
+            bullet = {
+                timerLimit = 0.5,
+                radius = 5,
+                speed = 500,
+                time = 4,
+            },
+        },
+        asteroids = {
+            stages = {
+                { speed = 120, radius = 15 },
+                { speed = 70,  radius = 30 },
+                { speed = 50,  radius = 50 },
+                { speed = 20,  radius = 80 },
+            },
+        },
+        controls = {
+            ship = {
+                turnRate = 10,
+                thrustRate = 100,
+            },
+        },
+    }
+end
+
+local game = initGame()
+
+local function initState()
+    local asteroids = {
+        {
+            x = 100,
+            y = 100,
+        },
+        {
+            x = game.width - 100,
+            y = 100,
+        },
+        {
+            x = game.width / 2,
+            y = game.height - 100,
+        }
+    }
+    for _, asteroid in ipairs(asteroids) do
+        asteroid.angle = love.math.random() * (2 * math.pi)
+        asteroid.stage = #game.asteroids.stages
+    end
+
+    return {
+        ship = {
+            x = game.width / 2,
+            y = game.height / 2,
+            angle = 0,
+            speed = {
+                x = 0,
+                y = 0,
+            }
+        },
+        -- the time after which the ship can fire another bullet
+        bulletTimer = game.ship.bullet.timerLimit,
+        bullets = {},
+        asteroids = asteroids,
+    }
+end
+
+local state = {}
+
+local function reset()
+    state = initState()
+end
+
+function love.load()
+    reset()
+end
+
+function love.update(dt)
+    if love.keyboard.isDown('right') then
+        state.ship.angle = state.ship.angle + game.controls.ship.turnRate * dt
+    end
+    if love.keyboard.isDown('left') then
+        state.ship.angle = state.ship.angle - game.controls.ship.turnRate * dt
+    end
+    state.ship.angle = state.ship.angle % (2 * math.pi)
+
+    if love.keyboard.isDown('up') then
+        local shipSpeed = 100
+        state.ship.speed.x = state.ship.speed.x + math.cos(state.ship.angle) * game.controls.ship.thrustRate * dt
+        state.ship.speed.y = state.ship.speed.y + math.sin(state.ship.angle) * game.controls.ship.thrustRate * dt
+    end
+
+    state.ship.x = (state.ship.x + state.ship.speed.x * dt) % game.width
+    state.ship.y = (state.ship.y + state.ship.speed.y * dt) % game.height
+
+    local function areCirclesIntersecting(aX, aY, aRadius, bX, bY, bRadius)
+        return (aX - bX) ^ 2 + (aY - bY) ^ 2 <= (aRadius + bRadius) ^ 2
+    end
+
+    for bulletIndex = #state.bullets, 1, -1 do
+        local bullet = state.bullets[bulletIndex]
+        bullet.timeLeft = bullet.timeLeft - dt
+        if bullet.timeLeft <= 0 then
+            table.remove(state.bullets, bulletIndex)
+        else
+            bullet.x = (bullet.x + math.cos(bullet.angle) * game.ship.bullet.speed * dt) % game.width
+            bullet.y = (bullet.y + math.sin(bullet.angle) * game.ship.bullet.speed * dt) % game.height
+        end
+        for asteroidIndex = #state.asteroids, 1, -1 do
+            local asteroid = state.asteroids[asteroidIndex]
+            if areCirclesIntersecting(bullet.x, bullet.y, game.ship.bullet.radius, asteroid.x, asteroid.y, game.asteroids.stages[asteroid.stage].radius) then
+                table.remove(state.bullets, bulletIndex)
+                if asteroid.stage > 1 then
+                    local angle1 = love.math.random() * (2 * math.pi)
+                    local angle2 = (angle1 - math.pi) % (2 * math.pi)
+                    table.insert(state.asteroids, {
+                        x = asteroid.x,
+                        y = asteroid.y,
+                        angle = angle1,
+                        stage = asteroid.stage - 1,
+                    })
+                    table.insert(state.asteroids, {
+                        x = asteroid.x,
+                        y = asteroid.y,
+                        angle = angle2,
+                        stage = asteroid.stage - 1,
+                    })
+                end
+                table.remove(state.asteroids, asteroidIndex)
+                break
+            end
+        end
+    end
+
+    state.bulletTimer = state.bulletTimer + dt
+    if love.keyboard.isDown('s') then
+        if state.bulletTimer >= game.ship.bullet.timerLimit then
+            state.bulletTimer = 0
+            table.insert(state.bullets, {
+                x = state.ship.x + math.cos(state.ship.angle) * game.ship.radius,
+                y = state.ship.y + math.sin(state.ship.angle) * game.ship.radius,
+                angle = state.ship.angle,
+                timeLeft = game.ship.bullet.time,
+            })
+        end
+    end
+
+    for _, asteroid in ipairs(state.asteroids) do
+        asteroid.x = (asteroid.x + math.cos(asteroid.angle) * game.asteroids.stages[asteroid.stage].speed * dt) %
+            game.width
+        asteroid.y = (asteroid.y + math.sin(asteroid.angle) * game.asteroids.stages[asteroid.stage].speed * dt) %
+            game.height
+
+        if areCirclesIntersecting(state.ship.x, state.ship.y, game.ship.radius, asteroid.x, asteroid.y, game.asteroids.stages[asteroid.stage].radius) then
+            reset()
+            break
+        end
+    end
+
+    if #state.asteroids == 0 then
+        reset()
+    end
+end
+
+function love.draw()
+    for y = -1, 1 do
+        for x = -1, 1 do
+            love.graphics.origin()
+            love.graphics.translate(x * game.width, y * game.height)
+            love.graphics.setColor(0, 0, 1)
+            love.graphics.circle('fill', state.ship.x, state.ship.y, game.ship.radius)
+            local shipCircleDistance = 20
+            love.graphics.setColor(0, 1, 1)
+            love.graphics.circle(
+                'fill',
+                state.ship.x + math.cos(state.ship.angle) * shipCircleDistance,
+                state.ship.y + math.sin(state.ship.angle) * shipCircleDistance,
+                5
+            )
+
+            for _, bullet in ipairs(state.bullets) do
+                love.graphics.setColor(0, 1, 0)
+                love.graphics.circle('fill', bullet.x, bullet.y, game.ship.bullet.radius)
+            end
+
+            for _, asteroid in ipairs(state.asteroids) do
+                love.graphics.setColor(1, 1, 0)
+                love.graphics.circle('fill', asteroid.x, asteroid.y, game.asteroids.stages[asteroid.stage].radius)
+            end
+        end
+    end
+end
diff --git a/main.lua b/main.lua
deleted file mode 100644
index 50c97cc..0000000
--- a/main.lua
+++ /dev/null
@@ -1,93 +0,0 @@
-local love = require("love")
-
-function love.load()
-    arenaWidth = 800
-    arenaHeight = 600
-    shipX = arenaWidth / 2
-    shipY = arenaHeight / 2
-    shipAngle = 0
-    shipSpeedX = 0
-    shipSpeedY = 0
-    shipRadius = 30
-
-    bullets = {}
-    bulletTimerLimit = 0.5
-    bulletTimer = bulletTimerLimit
-end
-
-function love.update(dt)
-    local turnSpeed = 10
-    if love.keyboard.isDown('right') then
-        shipAngle = shipAngle + turnSpeed * dt
-    end
-    if love.keyboard.isDown('left') then
-        shipAngle = shipAngle - turnSpeed * dt
-    end
-    shipAngle = shipAngle % (2 * math.pi)
-
-    if love.keyboard.isDown('up') then
-        local shipSpeed = 100
-        shipSpeedX = shipSpeedX + math.cos(shipAngle) * shipSpeed * dt
-        shipSpeedY = shipSpeedY + math.sin(shipAngle) * shipSpeed * dt
-    end
-
-    shipX = (shipX + shipSpeedX * dt) % arenaWidth
-    shipY = (shipY + shipSpeedY * dt) % arenaHeight
-
-    for bulletIndex = #bullets, 1, -1 do
-        local bullet = bullets[bulletIndex]
-        bullet.timeLeft = bullet.timeLeft - dt
-        if bullet.timeLeft <= 0 then
-            table.remove(bullets, bulletIndex)
-        else
-            local bulletSpeed = 500
-            bullet.x = (bullet.x + math.cos(bullet.angle) * bulletSpeed * dt) % arenaWidth
-            bullet.y = (bullet.y + math.sin(bullet.angle) * bulletSpeed * dt) % arenaHeight
-        end
-    end
-
-    bulletTimer = bulletTimer + dt
-    if love.keyboard.isDown('s') then
-        if bulletTimer >= bulletTimerLimit then
-            bulletTimer = 0
-            table.insert(bullets, {
-                x = shipX + math.cos(shipAngle) * shipRadius,
-                y = shipY + math.sin(shipAngle) * shipRadius,
-                angle = shipAngle,
-                timeLeft = 4,
-            })
-        end
-    end
-end
-
-function love.draw()
-    for y = -1, 1 do
-        for x = -1, 1 do
-            love.graphics.origin()
-            love.graphics.translate(x * arenaWidth, y * arenaHeight)
-            love.graphics.setColor(0, 0, 1)
-            love.graphics.circle('fill', shipX, shipY, shipRadius)
-            local shipCircleDistance = 20
-            love.graphics.setColor(0, 1, 1)
-            love.graphics.circle(
-                'fill',
-                shipX + math.cos(shipAngle) * shipCircleDistance,
-                shipY + math.sin(shipAngle) * shipCircleDistance,
-                5
-            )
-
-            for bulletIndex, bullet in ipairs(bullets) do
-                love.graphics.setColor(0, 1, 0)
-                love.graphics.circle('fill', bullet.x, bullet.y, 5)
-            end
-        end
-    end
-
-    love.graphics.origin()
-    love.graphics.setColor(1, 1, 1)
-    love.graphics.print(table.concat({
-        'shipAngle:' .. shipAngle,
-        'shipX: ' .. shipX,
-        'shipSpeedX: ' .. shipSpeedX,
-    }, '\n'))
-end