Very fun game, and well executed overall. Some sounds don't quite line up with the beat, which caused be to avoid using that gun since it annoyed me, but everything else was excellent, and enjoyable.
I think it would be cool if there were some more movement options/actions that could be executed on beat, for example a slide. Just to add to player expression and playstyles.
The music is great too.
Overall excellent submission, that should be getting a lot more attention.