Combat and collisions have a lot of issues. There were times when the bullet didn't collide with me, but I still took damage by it. Parrying doesn't seem to work, or unless I'm doing something wrong. Health packs would have been nice too. Especially as a reward system, since there wasn't one here. The last boss fight was disappointing, as I was just jumping and shooting for the entire time.
Some minor things are the soundtrack not fitting in with this kind of game. And when you have a credits scene, make sure to list not only the team members but also what their contribution to the project was.
Also, game breaking bug about the bullets not colliding with me: I jumped over one of the projectiles, but I somehow got killed by it and the screen froze. This happened during my second play through.