var Player = Container.expand(function () {
	var self = Container.call(this);
	var playerGraphics = self.createAsset('player', 'Player Graphics', .5, .5);
	self.speed = 5;
	self.move = function (direction) {
		switch (direction) {
			case 'left':
				self.x -= self.speed;
				break;
			case 'right':
				self.x += self.speed;
				break;
			case 'up':
				self.y -= self.speed;
				break;
			case 'down':
				self.y += self.speed;
				break;
		}
	};
});
var Minion = Container.expand(function () {
	var self = Container.call(this);
	var minionGraphics = self.createAsset('minion', 'Minion Graphics', .5, .5);
	self.speed = 5;
	self.move = function () {};
	self.attack = function () {};
});
var Enemy = Container.expand(function () {
	var self = Container.call(this);
	var enemyGraphics = self.createAsset('enemy', 'Enemy Graphics', .5, .5);
	self.speed = -5;
	self.move = function () {};
	self.attack = function () {};
});
var HeroBullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = self.createAsset('heroBullet', 'Hero Bullet Graphics', .5, .5);
	self.speed = 10;
	self.move = function () {};
});
var EnemyBullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = self.createAsset('enemyBullet', 'Enemy Bullet Graphics', .5, .5);
	self.speed = -10;
	self.move = function () {};
});
var Game = Container.expand(function () {
	var self = Container.call(this);
	var player = self.addChild(new Player());
	player.x = 2048 / 2;
	player.y = 2732 - 200;
	var keys = {
		left: false,
		right: false,
		up: false,
		down: false
	};
	function updatePlayerMovement() {
		if (keys.left) player.move('left');
		if (keys.right) player.move('right');
		if (keys.up) player.move('up');
		if (keys.down) player.move('down');
	}
	LK.on('tick', function () {
		updatePlayerMovement();
	});
	function handleKeyDown(event) {
		switch (event.key) {
			case 'ArrowLeft':
			case 'a':
				keys.left = true;
				break;
			case 'ArrowRight':
			case 'd':
				keys.right = true;
				break;
			case 'ArrowUp':
			case 'w':
				keys.up = true;
				break;
			case 'ArrowDown':
			case 's':
				keys.down = true;
				break;
		}
	}
	function handleKeyUp(event) {
		switch (event.key) {
			case 'ArrowLeft':
			case 'a':
				keys.left = false;
				break;
			case 'ArrowRight':
			case 'd':
				keys.right = false;
				break;
			case 'ArrowUp':
			case 'w':
				keys.up = false;
				break;
			case 'ArrowDown':
			case 's':
				keys.down = false;
				break;
		}
	}
	window.addEventListener('keydown', handleKeyDown);
	window.addEventListener('keyup', handleKeyUp);
	var minions = [];
	var enemies = [];
	var heroBullets = [];
	var enemyBullets = [];
	for (var i = 0; i < 5; i++) {
		var minion = new Minion();
		minion.x = 2048 / 2;
		minion.y = 2732 / 2 + i * 100;
		minions.push(minion);
		self.addChild(minion);
	}
	LK.on('tick', function () {
		for (var i = 0; i < minions.length; i++) {
			minions[i].move();
		}
		for (var i = 0; i < enemies.length; i++) {
			enemies[i].move();
		}
		for (var i = 0; i < heroBullets.length; i++) {
			heroBullets[i].move();
		}
		for (var i = 0; i < enemyBullets.length; i++) {
			enemyBullets[i].move();
		}
	});
	self.on('down', function (obj) {
		var pos = obj.event.getLocalPosition(self);
	});
});

===================================================================
--- original.js
+++ change.js
@@ -104,10 +104,10 @@
 				keys.down = false;
 				break;
 		}
 	}
-	LK.on('keydown', handleKeyDown);
-	LK.on('keyup', handleKeyUp);
+	window.addEventListener('keydown', handleKeyDown);
+	window.addEventListener('keyup', handleKeyUp);
 	var minions = [];
 	var enemies = [];
 	var heroBullets = [];
 	var enemyBullets = [];