Introduction

To date (Winter 2004) there have been two Aliens vs. Predator games released for the PC and Mac. Both have been published by Sierra, but have different developers, Rebellion for the original (AvP (1999)) and Monolith for its sequel (AvP2 (2001)). Rebellion released the source code to the first game in 2001, which made an unofficial port to Linux possible.

The games themselves are both first person shooters (FPS), but differ from most other FPS in that the player can choose the perspective to play from: Alien, Predator or Human (Colonial Marine or Corporate). These different perspectives afford distinct capabilities and weapons. In the most conventional case, playing as a human is the most similar to other FPS, and players are able to access a wide array of weaponry (mostly that from the films). As a Predator, players make use of Predator weapons such as the Plasmacaster, Disc and Wristblades. Predators are also somewhat more athletic than humans, can make use of a cloaking device to stalk prey, and have a range of different vision modes to aid them in hunting the other species. Playing as an Alien is the most significantly different perspective. Players are able to range freely over any surface regardless of its inclination. This allows wall-walking and completely novel means of attack. As an Alien, however, weaponry is restricted to claws, tail and jaws (for the infamous head-bite), though these themselves reward the player with a fairly unusual experience in FPS combat.

In the single player mode, both games present a conventional series of levels to progress through. However, because of the differing abilities of the three species, the levels themselves are not always conventional in structure - Alien levels, for instance, often involve climbing through convoluted buildings. In AvP, the levels are loosely structured, with progression sometimes a little arbitrary (e.g. Predator players find themselves, for a single level only, on the prison planet Fury 161 from the film Alien³). In both games, the storylines put the player in situations familiar to those who have seen the films

Plot Summaries

In the first game, the three single-player missions (Alien, Marine and Predator) are completely independent and never interconnect. However, the game includes bonus levels that allow each species access to portions of the missions of the other species. To allow the more three dimensional Alien levels to be played, Marine and Predator players are supplied respectively with a jetpack and grappling hook for these bonus missions.

Alien

In the opening cutscene, marines are in the process of securing a stone temple of unknown origin. An Alien drone (presumably you) wreaks havoc upon them.

• Temple: The Alien begins in the upper levels of the temple mentioned above. Marines have secured the lower levels of this temple, including your colony's hive. You must make your way to the hive, sealing off the strange energies that feed the temple and disrupting on-site research labs as you go.
• Escape: You must leave the hive and enter an adjacent human facility. As the marines repeatedly fail to contain or kill you, they issue a general evacuation order, and you must hitch a ride on a departing spacecraft (which happens to be carrying alien eggs).
• Ferarco: You find yourself aboard the Ferarco, a space freighter with a (well-armed) crew complement of fifty. The ship's interior is loosely based on that of the Nostromo from the movie Alien. The galley, the hypersleep vault, the landing-strut chamber, the observation bubble on the lowest deck, and the computer interface room should all be familiar to fans of the Alien series. After you destroy the interior of the computer interface room, the ship initiates a self-destruct procedure and you have a short amount of time to reach the escape shuttle (again from Alien).
• Gateway: The shuttle reaches Gateway Station in Earth orbit. Gateway was featured in the sequel to Alien, Aliens, although this time, fans won't find any familiar territory. Sensors detect a contaminant (you), and the airlock where the escape shuttle docked opens and you are nearly sucked into the vacuum of space. After escaping, you must make your way through the infrastructure of the station (mainly ventilation ducts), causing a minor power failure along the way. The marines are here, and they're more heavily armed than they were last time.
• Earthbound: You have reached Gateway's docking tower. Again moving through the ventilation system for the most part, you must reach a ship scheduled to depart for Earth. Near the end of the level, two Predators make an appearance on Gateway; you must kill them to proceed to Earth.

The end cutscene shows the Alien curled up inside a shuttlecraft with Earth, its destination, in view through a porthole.

Marine

The opening cutscene shows a facehugger attached to your character's face. However, as the facility alarms go off, your character sits bolt upright in bed and realises that this was just a nightmare.

• Derelict: The marine's game takes place ten years after the events of Aliens. The Company has built a research facility around the derelict ship which was the source of the original alien infestation, and marines like you are stationed there in case anything goes wrong. Needless to say, everything goes wrong. You're the last person to evacuate, and you must leave your quarters and make your way through the research facility to the derelict ship itself. After taking a lift down to the pilot's chamber (another familiar area from Alien), you reach the colony supporting the research facility.
• Colony: Once you take an elevator up to the surface, all that separates you from the comparative safety of a heavily-armored APC is the main gate. Unfortunately for you, it won't open. You've got to restore power, then hunt down an engineer's security card, which will allow you to escape. You find the card in a medlab reminiscent of the medlab in Aliens; in fact, all the corridors and structures are modeled in the same style as the colony buildings in Aliens. You get what you came for, open the gate, and run across open terrain toward the APC with Aliens hounding you all the way.
• Invasion: The APC brings you to an atmosphere-processing facility (a place featured in Aliens, although the interior in the game doesn't really resemble the movie sets). The Company won't let you leave unless you manually shut down five cooling valves to cause the facility's reactor to overheat (and, presumably, wipe out the Alien hive). You run around and turn the valves, then make your way to a landing pad where you are picked up by a dropship.
• Orbital: The dropship brings you to Odobenus Station in geosynchronous orbit above the planet. Somehow, Aliens have gotten loose here too. To make matters worse, Predators have taken an interest in the station as well. They destroy the dropship which brought you to the station, then forcibly board. You kill or dodge them and the many aliens in your path, making your way through crew quarters and a hydroponic lab. Along the way, you must also contend with an experimental security system consisting of "xenoborgs", Alien drones which have been converted to slow-moving but nearly indestructible cyborgs equipped with powerful lasers. You reach an escape pod which brings you to the Tyrargo.
• Tyrargo: The Tyrargo is a "Costenoga"-class ship (possibly a typo; the Sulaco, from Aliens, is said to be a "Conestoga"-class ship). Not surprisingly, it too has become infested with Aliens. You make your way through the very dimly-lit ship, passing familiar banks of cryotubes, hangars, and a mess hall (complete with a combat knife embedded in the table--a reference to Bishop's "knife trick"). After successfully killing an intruding Predator, the Company betrays you, informing you that you've been "most useful" and leaving you to die. However, after you kill a predalien hybrid, your commanding officer manages to open a door for a short period of time, allowing you to escape. You encounter praetorians, members of an intermediate caste of aliens between drones (which you've been fighting the whole time) and the queen. You take a service elevator down to the bowels of the ship, reaching the dropship hangar.
• Hanger: The dropship hangar is a large, open space, resembling a larger and better-lit version of the hangars you've seen in the previous level. Whatever weapons you had before are gone, leaving you with only a pulse rifle. Unfortunately, you face off against a queen alien in this room, and your rifle isn't going to do you a lot of good on its own. You must take advantage of the room itself to kill the queen, crawling under floor grating (like Newt in Aliens) and ultimately blasting the queen out loading airlock (again, like in Aliens). As the queen is sucked into space, you retreat into a sealed cubbyhole and watch.

In the ending cutscene, the marine watches as the queen is sucked out of the ship ... but he fails to notice the alien drone that has dropped behind him ...

Predator

The Predator's mission is not as coherent as the other species' missions, and takes the player through levels on three separate planets.

In the opening cutscene, an unwary marine fails to notice the predator's laser sight moving up his back ... and he is shot from behind with a bolt of plasma.

• Waterfall: The game begins with you stalking marines outside a military facility with the designation "Area 52" (compare this to Area 51). A Predator ship has been recovered and its occupant captured; your goal is to retrieve them. To this end, you stalk through several security checkpoints outside the base, finally reaching the entrance just past a waterfall.
• Area 52: In the second level, you are inside Area 52 and must fight your way deeper inside. Along the way, you need to retrieve a keycard. At the end of the level, you find your ship.
• Vaults: You retrieve two new weapons from your ship—your smart disk (which appeared in Predator 2) and a plasma pistol. You must destroy a series of computer banks to proceed further—but in doing so, you release the Aliens being held in the facility. The human occupants are quickly overrun and, as you progress, you find the labs where aliens were being held, studied, and dissected. You also find evidence that your comrade was taken here. In the deepest part of the lab, you find that the humans have experimentally infected your fellow Predator with an Alien—creating a Predalien hybrid. Upon releasing and killing the Predalien, you unintentionally trigger the facility's self-destruct system, giving you only a minute to reach your ship and escape.
• Fury 161: You travel to Fiorina "Fury" 161, the prison world featured in Alien 3. For unspecified reasons, there's an alien infestation on the planet and the marines are trying to clean it up. You pass through the lead-smelting facility and through some familiar scenes from the movie, including the morgue, the EEV crash-site, and the main hall. Finally, you reach the outside, and your ship arrives, allowing you to escape.
• Caverns: Your ship takes you to a marine-controlled Alien habitat. You fight your way through the human defenses, including xenoborgs and sentry guns, until you reach the Alien hive. After fighting a pair of praetorians deep in the hive, a rock floor collapses beneath you.
• Battle: The last level is a single room—the queen's chamber. You have disabled your powered weapons "to preserve your honor", leaving you with only your wristblades and your speargun. Unlike the marine's pulse rifle, your speargun is sufficient for this task, though you will expend most of your ammunition in the process.

In the ending cutscene, the Predator notices a lone facehugger sneaking up on it, and blasts it with the shoulder cannon.