The movie cirtic Nathan Donarum has brief post on Roger Ebert's blog where he wonders why the game "Gears of War" is in the film The Hurt Locker:
"On my second viewing of "The Hurt Locker," I noticed a curious detail. There is a scene in which Eldridge plays a video game. The video game is "Gears of War," a hyper-masculine, adrenaline-pumped game about...well, war. The main gameplay deals with firefights, and hiding behind different objects to avoid getting shot, and to avoid dying. It has a real focus on survival, and a real focus on the thrill of the fight."
His theory is that "Gears of War" was specifically picked because it defines the character who is playing it. That game is an accessory that is used for the character's development.