Thanks for the critics, the collision and wall detection are the same all over the levels, so I think it's important to show that the game needs precision since the beginning. For the graphics, I have real problems with the blurry effect ad don't really know to fixe that (if anyone has an idea I would appreciate, the game is made in GameMaker and it's original format is 320 x 240). I'll try to add a resolution menu in the next iteration.