Very well made and polished game, fun to play, for once not too hard :P Audio could use wome work, but it's ok.
I think the guns dissapearing after 10 seconds, while a clever idea, would be much better for the game as limited ammo instead (that's if you plan on finishing it later) - it's a bit annoying to run all the way back through the level to pick up a new weapon (though I realize that's part of the strategy, I'm just dumb :P).