You're really going to want to play that game (or any First Person Shooter)
with the keyboard and mouse rather than a gamepad, assuming you don't have
health reasons for not being able to do so. I would try the game out with
the default control mappings and you will get used to it eventually (and it
probably won't take that long; keyboard/mouse with a traditional WASD setup
is just "natural" for shooters).
--
smr