Yeah I played last night but was too busy too comment, and now I'm going to school lol. I'll comment later in more detail, but I'll sum up with good work so far
Edit: Okay, two things:
A) Looks like you got a movement in 8 directions problem, sometimes things don't work correctly. If you need help getting your code to work, just make a thread in novice, and I'll get around to fixing it.

While pretty fun, shooters that stand out are either those that are either brutally hard or very unique. This is mainly because, well, everyone's played a shooter, why bother playing one that's exactly like the others? You're working with large sprites, so it's hard to make a super hard "normal" shooter that's good, so I'd work on adding features that make your game more interesting.
Edited by greep, 22 February 2012 - 10:20 PM.