Definitely not an FPS. It's a stealth based action game. You know, sneak around, don't get caught, save the world from nuclear death? You can switch to first person view for precise shooting, but that's about as close to an FPS as you'll get.
As for the gameplay, the controls are super-wonky and the camera is horrible. I never thought that bad camera mechanics could kill a game, but in Splinter Cell: DA, it just e'ffing slaughtered it. Play it on the PS2 or Xbox360, hell of a lot better.