The game begins with a group of Colonial Marines making a grisly discovery on the planet LV-724. A massive war involving the Aliens and Predators has broken out. The Marines, for reasons known only to them, decide to get involved, further escalating the already savage affair. It's up to you to decide the fate of the planet after selecting one of the three races,
At first glance, Aliens versus Predator: Extinction seems like a great concept, and it is. However, the game never seems to gel, and begins to feel like a misguided, mindless quasi-RTS after only a few missions. Even though the game is labeled an RTS, much of the strategy that makes games like Rise of Nations, Age of Mythology and Warcraft work simply aren't present. It's the margarine of RTS's. The Diet Coke of RTS's, just one calorie, not RTS enough. But anyway...
Each of the three races has their own specific skills and attributes. Marines pack unmatched firepower and an assortment of troop types like medics and synthetics. Aliens can spawn offspring faster than a rabbit in heat and prove to be the most fun to play with since you have to cultivate eggs and find hosts for Facehuggers to infest. Predators are the real muscle of the three and tend to work in smaller groups, but they also get some of the better technology like healing suits and that cool cloaking device.
As expected, most of the game revolves around building up massive armies and destroying your enemies for control of the map. However, unlike a traditional RTS, AvP: Extinction places more emphasis on troop deployment and control rather than base building. You begin the game with a set unit of troops. As you work your way though the game's labyrinthine maps, you gain points which can be spent on either calling for reinforcements or upgrading your current tech.