If the framelimiter's on everyone will have a constant value of 30 frames per second, which will make the game equally difficult for everyone. If it's off it'll give out a variable rate which can range from 30-500 or even more, which theoretically makes the game faster for the person with the framelimiter off but that's BS. That person won't synch properly and all that'll happen is massive warps all over the screen.