Ah I see what you mean but then again I can, just that I can't turn around without using the mouse (right now I can't do that). Am using an n64 controller, using this thing called adaptiod that lets you use n64 controllers on your computer.
What I did is I set the analog stick for moving and the c-buttons for aiming. Z is for shooting A is for jumping, B is for alt-fire. I use the digital pad for switching weapons...ect
Though for a 8 button game pad, you won't be able to move back while shooting since your going to have to use the digital pad for aiming and moving. So pressing right/left would have you turn and move foward instead of just moving backwards, since you wouldn't be able to use another set of keys for aiming...blah blah