Of course there's a memory leak, the whole game is coded as one giant memory leak. As you hold down the mouse it creates a hundred objects every couple of seconds, and they are never deleted. Eventually you end up with tens of thousands of objects and then it dies.
Destroy objects when they go off the left of the screen!
Also, the layout doesn't need to be 99999x99999, it just makes the layout editor a pain to use. Make it 640x480 and enable 'unbounded scrolling', and you can go unto infinity (where infinity is 10^300 or something).