I tried to do the same. That doesn't work well on PC though. ):
I'm serious. The aiming SUCKS. That's why I missed so much. I had 100 percent accuracy on the Gamecube version. I'm down to 83 percent accuracy on this PC version.
You run with WASD. To pull out your knife, you hold down the left shift key and aim it with WASD. To pull out your gun, you hold down the right shift key and aim with WASD. It's incredibly annoying to have to use that WASD key combo to aim rather than the mouse.
YOU CAN'T EVEN USE THE FREAKING MOUSE IN THIS GAME.