I really like the cartoon style in this! My main concern is how much of a black hole the happy dude on the right is, as he's (without his knowledge) sucking up a lot of the surrounding light/life. Speaking of which, the surroundings are really nice :D
I'd say shade *reaaally* dark colors such as straight black with slightly lighter ones, such as deep purple. as to give more depth; I've seen it done a lot in comics :3
Oh my gosh, thank you so much! I will try my best to fix that problem!