I actually had a ton of fun playing the game. Hoards of enemies, powerful weapons, great SFX - I couldn't ask for more!
There are 2 things that could be improved in my opinion:
- Enemies are hard for me to notice (they blend with the environment)
- You could just make the reloading automatic, as in most games. If I were you, I'd just leave the "reloading" sign, but trigger it automatically. It can really help the pace of the game.