var JoyMeter = Container.expand(function () {
	var self = Container.call(this);
	self.joy = 0;
	self.maxJoy = 8;
	var joyMeterGraphics = self.createAsset('joyMeter', 'Joy Meter Graphics', 0.5, 0);
	joyMeterGraphics.y = 50;
	self.addJoy = function (amount) {
		self.joy = Math.max(0, self.joy + amount);
		if (self.joy > self.maxJoy) {
			self.joy = self.maxJoy;
		}
		joyMeterGraphics.width = 2048 / self.maxJoy * self.joy;
	};
	self.getJoy = function () {
		return self.joy;
	};
});
var Present = Container.expand(function () {
	var self = Container.call(this);
	var presentGraphics = self.createAsset('present', 'Present Graphics', .5, .5);
	self.speed = -10;
	self.move = function () {
		self.y += self.speed;
	};
});
var House = Container.expand(function () {
	var self = Container.call(this);
	self.speed = 2;
	self.move = function () {
		self.y += self.speed;
	};
});
var NaughtyHouse = House.expand(function () {
	var self = House.call(this);
	var houseGraphics = self.createAsset('naughtyHouse', 'Naughty House Graphics', .5, 1);
	houseGraphics.tint = 0xff0000;
	self.getNaughty = function () {
		return true;
	};
});
var NiceHouse = House.expand(function () {
	var self = House.call(this);
	var houseGraphics = House.prototype.createAsset.call(self, 'niceHouse', 'Nice House Graphics', .5, 1);
	houseGraphics.tint = 0x00ff00;
	self.hitCount = 0;
	self.getNaughty = function () {
		return false;
	};
	self.incrementHits = function () {
		self.hitCount++;
		if (self.hitCount >= 3) {
			self.transformToHappy();
		}
	};
	self.transformToHappy = function () {
		var happyHouse = new HappyHouse();
		happyHouse.x = self.x;
		happyHouse.y = self.y;
		LK.stage.addChild(happyHouse);
		self.destroy();
	};
});
var DarkHouse = House.expand(function () {
	var self = House.call(this);
	var houseGraphics = self.createAsset('darkHouse', 'Dark House Graphics', .5, 1);
	houseGraphics.tint = 0x808080;
	self.getNaughty = function () {
		return false;
	};
});
var HappyHouse = House.expand(function () {
	var self = House.call(this);
	var houseGraphics = self.createAsset('happyHouse', 'Happy House Graphics', .5, 1);
	houseGraphics.tint = 0xffff00;
	self.getNaughty = function () {
		return false;
	};
});
var Santa = Container.expand(function () {
	var self = Container.call(this);
	var santaGraphics = self.createAsset('santa', 'Santa Graphics', .5, .5);
	self.targetPosition = null;
	self.moveSpeed = 5;
	self.move = function (position) {
		if (position) {
			self.targetPosition = position;
		}
		if (self.targetPosition) {
			var dx = self.targetPosition.x - self.x;
			var dy = self.targetPosition.y - self.y;
			var distance = Math.sqrt(dx * dx + dy * dy);
			if (distance > 1) {
				var angle = Math.atan2(dy, dx);
				var tentativeX = self.x + Math.cos(angle) * self.moveSpeed;
				var tentativeY = self.y + Math.sin(angle) * self.moveSpeed;
				self.x = tentativeX;
				if (tentativeY > 2732 - 2732 / 3) {
					self.y = tentativeY;
				}
			} else {
				if (self.targetPosition.y > 2732 - 2732 / 3) {
					self.x = self.targetPosition.x;
					self.y = self.targetPosition.y;
				}
				self.targetPosition = null;
			}
		}
	};
});
var Game = Container.expand(function () {
	var self = Container.call(this);
	var houses = [];
	var presents = [];
	var joyMeter = self.addChild(new JoyMeter());
	LK.gui.topCenter.addChild(joyMeter);
	var santa = self.addChild(new Santa());
	santa.x = 2048 / 2;
	santa.y = 2732 - 2732 * 0.1;
	var presentFireRate = 60;
	var presentFireCounter = 0;
	stage.on('down', function (obj) {
		var pos = obj.event.getLocalPosition(self);
		santa.move(pos);
	});
	LK.on('tick', function () {
		santa.move();
		if (presentFireCounter++ >= presentFireRate) {
			var present = new Present();
			present.x = santa.x;
			present.y = santa.y;
			presents.push(present);
			self.addChild(present);
			presentFireCounter = 0;
		}
		if (Math.random() < 0.02) {
			var houseTypes = [NaughtyHouse, NiceHouse];
			var randomHouseType = houseTypes[Math.floor(Math.random() * houseTypes.length)];
			var house = new randomHouseType();
			house.x = Math.random() * 2048;
			house.y = -house.height;
			houses.push(house);
			self.addChild(house);
		}
		for (var i = presents.length - 1; i >= 0; i--) {
			var present = presents[i];
			present.move();
			if (present.y < -present.height) {
				present.destroy();
				presents.splice(i, 1);
			} else {
				for (var j = 0; j < houses.length; j++) {
					var house = houses[j];
					if (present.intersects(house)) {
						if (house.getNaughty()) {
							joyMeter.addJoy(-3);
							var darkHouse = new DarkHouse();
							darkHouse.x = house.x;
							darkHouse.y = house.y;
							self.addChild(darkHouse);
							house.destroy();
							houses.splice(j, 1);
							houses.push(darkHouse);
						} else {
							joyMeter.addJoy(1);
							if (house instanceof NiceHouse) {
								house.incrementHits();
							}
						}
						present.destroy();
						presents.splice(i, 1);
						break;
					}
				}
			}
			for (var h = houses.length - 1; h >= 0; h--) {
				var house = houses[h];
				house.move();
				if (house.y > 2732 + house.height) {
					house.destroy();
					houses.splice(h, 1);
				}
			}
		}
	});
});

===================================================================
--- original.js
+++ change.js
@@ -31,9 +31,9 @@
 	};
 });
 var NaughtyHouse = House.expand(function () {
 	var self = House.call(this);
-	var houseGraphics = House.prototype.createAsset.call(self, 'naughtyHouse', 'Naughty House Graphics', .5, 1);
+	var houseGraphics = self.createAsset('naughtyHouse', 'Naughty House Graphics', .5, 1);
 	houseGraphics.tint = 0xff0000;
 	self.getNaughty = function () {
 		return true;
 	};