Thanks a lot for your feedbacks!
For the slimes the shop is a good idea, I will white it down somewhere. Maybe I could also add ransow animation that occurs time to times :)
For aether realm you are right, it is set by default on the european keyboard (azerty). I also put a another control on the arrow keys but I should do something for the qwerty keyboard :/ I didn't know about the rendering bug, I will remember it for next time I work on the game. About the colors it's a good think you want more: actualy, if you collect enough power balls, you begin to color the world around you. First you only color rocks, then you color plants, then water (my favourite) and finaly fire-linked elements.
Once again thanks for your feedbacks, they were realy usefull ^^