I really enjoyed this game, and beat it after several attempts at taking the boss. The concept is really cool, and I like the way the game alerts you of enemies. The fact that the alerts are inconsistent always puts you on edge, which I like.
The real star of the show here is the boss battle at the end, and while 50 hits was quite repetitive, I wouldn't really expect things to be mixed up too much considering the time constraint.
Sound effects are great. Bonus points for the Wilhelm scream. Otherwise, the animations were really nice. Well done!