Oops, guess the readme wasn't included with the installer or something, you can find it here (right click+save as):
https://raw.githubusercontent.com/Gr...aster/help.rtf
Only 30fps shows are supported atm, but this will change eventually, it shouldn't be hard to support other framerates. But for now, if you try to play a 75fps show it should play very slowly.
Exactly what CPU and graphic card do you have? Are they better than the ones listed in the readme linked above? And what does the fps indicator in the corner say?
One thing you can do to improve performance is press B to disable the fog shaders. And I will add more performance options later, like custom anti-aliasing levels and resolution.