Fun game, nice work! I liked the difficulty balance, very easily to suddenly find you're nearly out of energy but there's generous amount of health pickups if you can get back to them. I couldn't work out if something odd is going on with the bullets - I felt like the occasional bullet was much faster than normal but couldn't really be sure. I did get stuck at one point, collided quite fast with the corner of a wall and then I couldn't move away, just rotate on the spot.