The game contains three playable races, consisting of Human, then Alien, and finally Predator.
The physically weakest of all the races, Humans take damage from falls easily and must rely on weapons to combat the other two races, and the starting race.
They have several weapons at their disposal, including Pistols, the basic weapon with unlimited ammunition, to Miniguns/Rifles with fairly large clips,and Rocket Launchers with about 3-4 shots.
The Human goal is to rescue all other humans and remove Facehuggers from them before the Chestbursters inside mature enough to kill them.
The fastest and physically strongest of all the races, Aliens can crawl on walls, allowing them to ambush both Humans and Predators. They are unlocked by beating all Human levels and are the second race.
They cannot use weapons aside from their organic ones (Claws), and automatically lay Facehuggers on humans they kill, leaving predator without them.
The Alien goal is to kill any opposition found in the Pyramid and find suitable hosts for the Facehuggers, while growing in size and power through the levels, from a Drone to a Warrior and finally a Queen or an Alien roughly that size.
The Slowest of all the races, they take no damage from large falls, can jump remarkably high, and rely on weapons to destroy their opponents. They are unlocked after beating all Alien levels and are the final race.
The starting weapons for the Predators are Wristblades, short range melee weapons that are fairly weak in comparison to the starting weapons of the other two races. Scattered around the Temple are Combi-Sticks, larger Spears with a longer reach and more power then the Wristblades, and Plasma Blasters, handheld Plasma Casters the are quite powerful and slow, and can only contain four blasts.
The Predator goal is to kill the other two races who inhabit the Temple and take the Skulls of worthy opponents.