Best game I've played yet, hands down. The main mechanic is awesome and is executed really well. The color pallet swapping is really cool, I haven't seen that before. The gameplay is super fun and the visuals and sound effects are amazing. The only 'bad' thing I can think of is that there's no way to regain health.
ALSO THANK YOU SO MUCH FOR HAVING THE GUN AUTO-FIRE. WHY DON'T MORE GAMES DO THAT?