The soundtrack to this is banging! It's really awesome. I'm so jealous, I've tried to get a chiptune sound before but with no success. I completed the game, but couldn't beat DSD! I might go back now that I have played the other games and see if I can beat him. I found the game genuinely fun with some cool level design.
I have one piece of constructive criticism, that I hope doesn't annoy you! But I think if Scratch killed normal enemies in one hit when he was at full ego, it would make the player feel super powerful and really push you to reach max ego and not want to loose it. I hope you don't mind me saying. I think I have some issues with enemy HP in my game too! I found it hard to get a good balance.
Overall it's a cool game, it was the first one I played in the Jam and it stuck with me!