Dude, I went on it, and first thing that happened was I fell through the floor. WTF?!?!!?!?!? You need to fix your actionscript, or fix the line, you did name it "ground" (or whatever it was in the actionscript) in the instance bit right? oh and when you press shift it keeps shooting, doesn't just do it once.
Checkl your action script, instance names, and check the lines have no holes or anything.
Good idea though.