Well, honnestly, guys, there's really nothing to get arguing about here.
I need advices to progress, that's certainly a fact. You gave pretty good ones, and i'm grown up enough to take critics the way they are, even if they are as rude as "less interesting than kirby". I'm not doing pixel art "like this" for 10 years, fortunately. I'm just getting back at "pixel drawing" after 10 years, and i'm sure amazed at what you guys manage to do with e.g. Arne's palette.
I don't have such skillz yet, and i'm doing both the code and the gfx on this project, meaning that if i later find someone that's doing better art than myself, everything you see might become "concept art" rather than "ingame art"
I just wish people had given crits over the complete character (e.g. the ball with hands and feet), but it's my bad to have posted straight screen capture rather than game mockup, so i can't complaint.
I'll get back to work now, try to integrate your remarks, work on better animation and palette manipulation tools, add rayman-like animation to the main character, and come back when i'll consider to have any improvement.