Good entry, nice graphics that fit well with the 64x64 restriction, and interesting concept.
Suggestion: I would have used the mouse to move the aim up/down instead of W, S. I think it'd be more intuitive that way.
Note: the web version is not working for me, it never starts loading.
Note 2: the Windows version crashes when you are modifying the audio in the menu, and could never start the game again, I had to download it again for some reason.