This is pretty fun to play, the main mechanics are already solid and I didn't found any important bug, that HP counting is really interesting too, I was expecting that kind of shump where you die with only one hit.
The only problem I had was the thing Sinoc posted, sometimes I didn't know that an enemy was destroyed because I was too busy dodging bullets and there wasn't any sound or graphical effect to make me notice that even if I'm not looking directly to it, and I really need to know that because if that doesn't happens I can stay the same place and ignore the other enemies.