var Bubble = Container.expand(function () {
	var self = Container.call(this);
	var bubbleGraphics = self.createAsset('bubble', 'Bubble Graphics', .5, .5);
	self.move = function () {};
	self.pop = function () {};
});
var Game = Container.expand(function () {
	var self = Container.call(this);
	var bubbles = [];
	var spawnBubble = function () {
		var newBubble = new Bubble();
		bubbles.push(newBubble);
		self.addChild(newBubble);
	};
	LK.on('tick', function () {
		for (var i = 0; i < bubbles.length; i++) {
			bubbles[i].move();
		}
	});
});

===================================================================
--- original.js
+++ change.js
@@ -15,9 +15,6 @@
 	LK.on('tick', function () {
 		for (var i = 0; i < bubbles.length; i++) {
 			bubbles[i].move();
 		}
-		if (LK.ticks % 60 == 0) {
-			spawnBubble();
-		}
 	});
 });