var SlowCloud = Container.expand(function () {
	var self = Container.call(this);
	var cloudGraphics = self.createAsset('cloud', 'Cloud Graphics', .5, .5);
	cloudGraphics.scale.x *= 2;
	cloudGraphics.scale.y *= 2;
	self.speed = (Math.random() * 1 + 1) * 2;
	self.move = function () {
		self.x -= self.speed;
		if (self.x <= -cloudGraphics.width) {
			self.x = 2048 + cloudGraphics.width;
			self.y = Math.random() * 2732;
		}
	};
});
var MediumCloud = Container.expand(function () {
	var self = Container.call(this);
	var cloudGraphics = self.createAsset('cloud', 'Cloud Graphics', .5, .5);
	cloudGraphics.scale.x *= 4;
	cloudGraphics.scale.y *= 4;
	self.speed = (Math.random() * 2 + 1) * 4;
	self.move = function () {
		self.x -= self.speed;
		if (self.x <= -cloudGraphics.width) {
			self.x = 2048 + cloudGraphics.width;
			self.y = Math.random() * 2732;
		}
	};
});
var FastCloud = Container.expand(function () {
	var self = Container.call(this);
	var cloudGraphics = self.createAsset('cloud', 'Cloud Graphics', .5, .5);
	cloudGraphics.scale.x *= 6;
	cloudGraphics.scale.y *= 6;
	self.speed = (Math.random() * 3 + 1) * 6;
	self.move = function () {
		self.x -= self.speed;
		if (self.x <= -cloudGraphics.width) {
			self.x = 2048 + cloudGraphics.width;
			self.y = Math.random() * 2732;
		}
	};
});
var Explosion = Container.expand(function () {
	var self = Container.call(this);
	var explosionGraphics = self.createAsset('explosion', 'Explosion Graphics', .5, .5);
	explosionGraphics.scale.x *= 2;
	explosionGraphics.scale.y *= 2;
	self.duration = 30;
	self.tick = function () {
		self.duration--;
		if (self.duration <= 0) {
			self.destroy();
		}
	};
});
var Missile = Container.expand(function () {
	var self = Container.call(this);
	var missileGraphics = self.createAsset('missile', 'Missile Graphics', .5, .5);
	missileGraphics.scale.x *= -4;
	missileGraphics.scale.y *= 4;
	self.gameDuration = 0;
	self.speed = -20 - self.gameDuration * 5;
	self.move = function () {
		self.speed = -20 - self.gameDuration * 2.5;
		self.x += self.speed;
	};
});
var Superman = Container.expand(function () {
	var self = Container.call(this);
	var supermanGraphics = self.createAsset('superman', 'Superman Graphics', .5, .5);
	self.hitCount = 0;
	self.move = function (x, y) {
		self.x = x;
		self.y = y;
	};
});
var Game = Container.expand(function () {
	var self = Container.call(this);
	LK.stageContainer.setBackgroundColor(0x0000ff);
	var clouds = [];
	for (var i = 0; i < 3; i++) {
		var slowCloud = new SlowCloud();
		slowCloud.x = Math.random() * 2048;
		slowCloud.y = Math.random() * 2732;
		clouds.push(slowCloud);
		self.addChild(slowCloud);
	}
	for (var i = 0; i < 3; i++) {
		var mediumCloud = new MediumCloud();
		mediumCloud.x = Math.random() * 2048;
		mediumCloud.y = Math.random() * 2732;
		clouds.push(mediumCloud);
		self.addChild(mediumCloud);
	}
	for (var i = 0; i < 3; i++) {
		var fastCloud = new FastCloud();
		fastCloud.x = Math.random() * 2048;
		fastCloud.y = Math.random() * 2732;
		clouds.push(fastCloud);
		self.addChild(fastCloud);
	}
	var superman = self.addChild(new Superman());
	var missiles = [];
	superman.x = 100;
	superman.y = 2732 / 2;
	var isGameOver = false;
	var tickOffset = 0;
	var gameDuration = 0;
	var gameDurationText = new Text2('0', {
		size: 150,
		fill: '#ffffff'
	});
	gameDurationText.anchor.set(.5, 0);
	LK.gui.topCenter.addChild(gameDurationText);
	LK.on('tick', function () {
		if (isGameOver) {
			LK.effects.flashScreen(0xff0000, 1000);
			LK.showGameOver();
		}
		for (var a = missiles.length - 1; a >= 0; a--) {
			if (missiles[a]) {
				missiles[a].move();
				if (missiles[a].x < -50) {
					missiles[a].destroy();
					missiles.splice(a, 1);
				}
				if (superman.intersects(missiles[a])) {
					var explosion = new Explosion();
					explosion.x = missiles[a].x;
					explosion.y = missiles[a].y;
					self.addChild(explosion);
					missiles[a].destroy();
					missiles.splice(a, 1);
					superman.hitCount += 1;
					if (superman.hitCount >= 4) {
						isGameOver = true;
					}
				}
			}
		}
		clouds.forEach(function (cloud) {
			cloud.move();
		});
		if (tickOffset++ % 60 == 0) {
			gameDuration++;
			gameDurationText.setText(gameDuration);
		}
		if (tickOffset % 30 == 0) {
			var newMissile = new Missile();
			newMissile.x = 2048;
			newMissile.y = Math.random() * 2732;
			newMissile.gameDuration = gameDuration;
			missiles.push(newMissile);
			self.addChild(newMissile);
		}
		self.children.forEach(function (child) {
			if (child instanceof Explosion) {
				child.tick();
			}
		});
	});
	var dragNode = null;
	stage.on('down', function (obj) {
		dragNode = superman;
	});
	function handleMove(obj) {
		var event = obj.event;
		var pos = event.getLocalPosition(self);
		if (dragNode) {
			dragNode.move(pos.x, pos.y);
		}
	}
	stage.on('move', handleMove);
	stage.on('up', function (obj) {
		dragNode = null;
	});
});

===================================================================
--- original.js
+++ change.js
@@ -2,9 +2,9 @@
 	var self = Container.call(this);
 	var cloudGraphics = self.createAsset('cloud', 'Cloud Graphics', .5, .5);
 	cloudGraphics.scale.x *= 2;
 	cloudGraphics.scale.y *= 2;
-	self.speed = Math.random() * 1 + 1;
+	self.speed = (Math.random() * 1 + 1) * 2;
 	self.move = function () {
 		self.x -= self.speed;
 		if (self.x <= -cloudGraphics.width) {
 			self.x = 2048 + cloudGraphics.width;