The biggest problem is with the car chases that basically make it essential to pick a machine gun as your primary, rather than sniper for those that prefer stealth - that's not as much of an issue for me, though a friend is finding the game quite a chore as sniper. Other than that the combat is great fun.
Tell your friend to get a light machine gun. It goes in the special slot. My loadout is either silenced pistol/sniper/machine gun or grenade launcher/sniper/machine gun. This comment was edited on Oct 24, 2008, 16:36.