Amazingly done in only 4 hours! The game feels great to play, with the particle effects, sound effects, screen shake. I think all the effort (or time) you put into that really payed off. At first it caught me of guard that the dead bodies also killed me, but then I remembered that 'dont touch anything red' and I understood it immediately :) The three different guns were also truely different and had a siginificant impact on the gameplay. One little thing is that sometimes I got the same gun twice in a row, but that is no big deal.
One thing that bothered me is that the music restarts when you die. Because dying is pretty common in this game (at least for me :P) it is pretty jarring when the music stops suddenly. If the music were to just continue I would feel more motivated to try again. (Maybe this is just me though.)
Really well done! I enjoyed this one a lot :D