when vsync is disabled the game is more reactive and shoppa style is really more playable (there aren't input lags); it would be nice an option to turn it on and off: however it can be disabled (in windows 0.9.17 version it seems already disabled) modifying the sources and recompiling the game
ps. this happens with an ATI Radeon 5670, I don't know if even with nVidia cards you will have this issue