I recently downloaded the demo on Steam. I can start the game and it seems to run fine, but I can't move left or right. Pressing A or D does nothing. I can still crouch and jump though. Some other keys might not work either, but I can't really tell.
Also the mouse cursor flickers when I move it, and dissapears when it's not moving.
I'm thinking the moving problem might have something to do with gamepad, but I'm not using one nor am I using a gamepad program. So I'm not sure how that would mess anything up, but in another game I have (Recettear), the controls were messed up so I disabled gamepad settings and it fixed it. I can't do that with this game though because when I try to click the gamepad control when editing it, it blips on then off and wont let me do anything with it.