At first, it was hell, I couldn't figure out how to control the character at all, I constantly flew off the walls, crashed and lost speed. Then it dawned on me that you can jump up on the run and make a slide, and it greatly boosts your speed. And I also killed the boss once because of a bug, I flew up into the sky, landed on the eye and smashed it standing right on it :)
Red sky and big watching eye looks so cool!