the game is actually very good, although it can use more textureing and a better control set in my opinion.
Any way, here is the link: http://isnooky.freehostia.com/games/fangames/sa3/ ,And the controls are:
WASD: movement.
Mouse: camera.
Left mouse button: ring dash (Sonic only).
Shift: Spindash /Attack (not available in the early demos)
Space: jump.
Try it out and tell me how ya like it!
