Cool, short and sweet game! I only managed to get to world 3, and after a few attempts I gave up because it was just a bit too hard, but that's probably because I suck at platformers lol. Something you could have done to make the controls feel a little better was adding coyote time or jump buffering, so maybe those could be additions to your next platformer!
The art was simplistic and nice, and the game had a neat premise. I think I found a shortcut in world 2 to skip to the next stage just at the start which was pretty funny. I like how the game implements the theme, as the player kind of has to balance killing or not killing the enemies that frustrate them so.
Nice work.