Finally I found some time to play your game and it played very good! I really liked how you introduced new mechanics and enemies step by step. Also the idea that you do not kill the enemies (directly) and need to push them from the platform is very good. The difficulty is also set very well as it gets gradually more difficult but never too difficult. I like the music, but maybe you could make it loop a bit better.
I also tried the gamepad and it plays very well. I had the impression it is more difficult with the gamepad, but maybe I am just an old keyboard/mouse PC gamer :D.
Congratulations to this cool game and doing the extra 13kB challenge!