You know what to press. The game is slowed more the higher FPS you put in the slider, but there are more frames of more positions. This means you can do 240 FPS frame-perfects and all that. TAS runs may be a lot more chunky on 60+ FPS. Z and C to change slider amounts from 30 to 240.
Apparently the floor detection glitches at >30 FPS so I fixed it with an extra step.