for multi buttons:
(my menu is in french, and I'm too lazy to set it to english, so it's approximative
An option to tune frame limiter and set it manually under 50 fps has been requested to Schtruck recently, I think he's currently working on it.
But it's weird to see this game running to fast when fps are what they are supposed to be
While waiting for Schtruck to create this framelimiter settings, you can try:
1) get a PAL version of the game, it's supposed to be 10 fps slower than an NTSC game
2) try to set more options in video settings, more filterings, etc (some will certainly bring gfx glitches, so don't keep them!) but using anti-aliasing+every filtering, etc will certainly slow the game down