At its core, Alpha Protocol is a third person action game much like many of Obsidians other games. After the initial tutorial mission you are asked to specialise in one of three areas (such as commando or spy) or become a recruit and build your unique character. How you choose to play can be determined by this decision and cannot be changed once you have made your decision. It can be a game like Gears of War and third person shooting dominating, or a more placid, Splinter Cell style game where you sneak into buildings rather than go all guns blazing.
