The game has good graphics, what engine did you use for it? For changes, I recommend lowering his acceleration speed and allowing sonic to gain speed off of slopes. Also, the camera being a little bit more zoomed in could give a stronger sense of speed. If possible in your engine, try adding 360 degree movement, or at least scripted loops. Other than that, this game is good. What levels will you be adding? So far,I think the idea of a moving screen in a level hadn't occurred to me yet.
Oh, Thanks! ^^ i Used "Clickteam Fusion" to make this game, ok, i will lower his acceleration, but I do not know if I'll be able to do the Slopes and Loops business, because this is my first game on this Engine, and well, I'm going to add the Stages: Jungle Zone, Labyrinth Zone, Underground Zone, Sky High, Turquose Hill, Sunset Park, and Mecha Green Hill Zone