Aliens Versus Predator: Extinction is a video game released in 2003 for the PlayStation 2 and Xbox. It is a Real-time strategy game in which a Alien hive, a Clan of Predators and an elite squad of Colonial Marines fight each other in 21 single-player missions. Each race has its own characteristics, abilities, weapons, and vehicles.
Unlike as in the most other Real-time strategy games in Aliens Versus Predator: Extinction the player(s) don't have to do any building and base construction. The game is strictly focused on unit management and combat. Each race has a distinct method of obtaining new troops.
The colonial marines gain credits by killing enemies and repairing atmosphere generators, and these credits can be put toward upgrading troop abilities and calling in new units via dropships that stop at nearby landing beacons. There are a diverse number of marine combat units, including pulse rifle-equipped infantry, flamethrower troopers, and smartgunners. The Colonial Marines also have three support units, one for healing and a synthetic which can deploy gun turrets and has a motion detector for picking up offscreen movement, the third unit, the commtech is the basic support unit, whose job it is to call for extra troops and repair atmosphere generators.
The predators have a straightforward resource model that's effectively based on honor. As the player kill enemies, he can rip the skulls from their corpses in honor of the hunt. The more honor the player has, naturally, the more predators will want to join the clan. They can be called in at any time and simply land on the planet from space. The predator units are all combat-oriented, and they have a number of special abilities like cloaking and self-healing that use up slowly regenerating energy points.
The aliens' method of building revolves around a Alien queen, which can deliver attacks and also remains in the hive to lay eggs. The eggs hatch into facehuggers who can latch onto other creatures and impregnate them with an egg that will eventually become a fully grown alien. There are two kinds of facehuggers that correspond to two kinds of aliens—purebreeds and transbreeds. The purebreeds include the queen and a couple of other powerful aliens, while the transbreeds are spawned from regular facehuggers, and the kind of alien the player get depends on what kind of host was impregnated. Cattle-like oswocs will yield a drone, which is the worker of the alien hive, while a warrior alien will be birthed from a human, a runner Alien will emerge from kirns and a predalien will spawn from an impregnated predator.
Differences between the PS2 and Xbox Versions
On the Xbox it has a higher framerate and less aliasing 
All in all AvP:Extinction received mixed but overall positive reviews by gamesites. GameSpot wrote "Extinction does a good job of translating Aliens Versus Predator to an RTS, but it could have benefited from a few more months in development."  GameSpot review and gave it a 7.2 out of 10.