With resolution 640x480 game works 73-75 fps (Vsync) on my weak Pentium 4 PC (Around 2GHz single core, 504Mb, 50-60Gb slow HDD)
But after trying to use 800x600 resolution (recommended resolution without problems with interface), fps was around 6-7 fps.
I agree my PC is pretty much "potato winner" quality, and maybe even Exagear RPi 3 powered PC could do better than this (more RAM available, better GPU available with more GPU memory, CPU has weaker clocks but is quad core)