Seems like it's happening when you don't get enough people... And the spaceship does not come back with people + it does not seem to be able to go again.

I'm finding these errors: java.lang.Exception: Stack trace at java.lang.Thread.dumpStack(Unknown Source) at Town.loose(Town.java:101) at BuildableObject.addedToWorld(BuildableObject.java:199) at greenfoot.World.addObject(World.java:401) at BuildingPrototype.finishConstruction(BuildingPrototype.java:23) at BuildingPrototype.act(BuildingPrototype.java:16) at greenfoot.core.Simulation.runOneLoop(Simulation.java:346) at greenfoot.core.Simulation.run(Simulation.java:178)

I should probably clear away powerups too after pressing "a"... @mjrb and anyone else: What type of visual change would look good here?

Well the "a" is just temporary until i can get a load level function and an opening screen... I'll try to make it so that the ball returns to the paddle before the next level loads.