Good fun, I like the style
The run and gun style is good fun :-D I didn't have time to give it a good play through, but basically:
1. Graphics are nice, and animation is good
2. Bullets need to "travel" - someone already mentioned this. I find this a quality missing from many shooters with mouse controlled shooters. Bullets won't hit the target unless you are pointing at them = frustrating. This gets annoying after a while, especially in more difficult stages
3. Gun SFX need to sound more gutsy.
Otherwise good fun, but a bit repetitive and I wouldn't find myself coming back after an initial gaming session.