Very cool! I got to the end (had to press R to reset on a level or two, reading the other comments you might want to put that in the description) and it was pretty fun. At first, I didn't realize enemies hitting other enemies would hurt you, or hurting yourself with non-enemy associated items (like the bombs) would hurt a random enemy, but in the later levels (specifically after the three spinning guys hitting the bombs) I wrapped my head around it. Great job!