Metroid Fusion Cheats :
SpEed Boost Slam
After you beat Serris and get the Speed Boost, run until it starts up, stop, press down, and either: Right(or left) + A or Up + A, if you go to the right or left it will look like Samus is doing a football tackle. If you do up Samus will look like an upward flying bullet. You gotta do this quick though or the boost will end.