I just upgraded to Windows 8.1 on my laptop. Before, the system ran fine. The game is now unplayable in Windows 8.1. No matter how careful you are, the mouse jumps up or down so no matter what you're looking at either the sky or the floor. It seems the rest of the system lags at the same time, but if you don't use the mouse for a bit, you can run around just fine at full FPS.
Pressing escape brings up the menu, but it usually takes a second or two to pop up.
Pressing escape brings up the menu, but it usually takes a second or two to pop up.
Seems a bit foolish I didn't try this first.