java.security.AccessControlException: access denied (java.io.FilePermission sound.wav read) java.lang.NullPointerException at world.act(world.java:58) at greenfoot.core.Simulation.actWorld(Simulation.java:509) at greenfoot.core.Simulation.runOneLoop(Simulation.java:452) at greenfoot.core.Simulation.runContent(Simulation.java:199) at greenfoot.core.Simulation.run(Simulation.java:187)

It doesn't really work here on the gallery. I'm getting an exception: java.lang.StringIndexOutOfBoundsException: String index out of range: -1 at java.lang.String.substring(Unknown Source) at Finder.act(Finder.java:46) at greenfoot.core.Simulation.actActor(Simulation.java:503) at greenfoot.core.Simulation.runOneLoop(Simulation.java:466) at greenfoot.core.Simulation.runContent(Simulation.java:199) at greenfoot.core.Simulation.run(Simulation.java:187)

I think it would be better if you could fall down. I find it really frustrating when I jump up continuously and then have no support platform below me. You could also make the platforms disappear after you jump on them so that if you do drop, you'll have a harder time finding a platform.