Area 51 is a First-Person Shooter video game on the UnrealEngine 2 and released on the Playstation 2, Xbox, and PC. Based loosely on the 1995 arcade rail shooter of the same name, the game takes place inside the famous Area 51 research facility in Groom Lake, Nevada, where the release of an alien virus has transformed the majority of the scientists and security staff into insane raging mutants. The player takes the role of Ethan Cole, a member of a 4-man biohazard cleanup team sent into the facility to contain the situation. As the game progresses Ethan is eventually separated from his team and ends up uncovering a massive conspiracy between the world-controlling Illuminati and the alien Greys who crash landed in the Nevada desert 50 years ago.A Non-Linear Sequel, named Blacksite: Area 51, was released in 2007. Built on the Unreal Engine 3 (aka the Gears of War engine), Blacksite featured similar themes and gameplay elements to the original game, but took place in a different continuity. This time the player is Aaron Pierce, the Silent Protagonist leader of a 4-man team of Delta Force operators who encounter alien phenomenon during the invasion of Iraq in 2003. Three years later, Pierce and his team are called in to suppress an armed insurrection in the area around Rachel, Nevada, only to discover the town and surrounding environs are crawling with alien lifeforms as well as a small, well-organized army of hostile cyborg soldiers known as the Reborn. Blacksite is infamous for being an Obvious Beta that was rushed out into publication before being properly finished as well as being Anvilliciously political. Which contributed to the game's mediocre reception, which combined with Midway crashing and burning a year later, makes further entries into the series rather unlikely for the near future.
Area 51 and Blacksite shows examples of the following tropes:
Artificial Brilliance: The A.I. of the Reborn soldiers in Blacksite isn't anything revolutionary, but given how utterly broken many aspects of the game are it's somewhat surprisingly the A.I. system was actually fully functional and generally up to the standards of the period (i.e. taking cover, tossing grenades, advancing from cover to cover intelligently, reacting and changing position based on the player's position). In fact the friendly A.I. was actually more useful than one in many better made shooters; they threw grenades often and quite skillfully, and with high morale could mow their way rather well through most of an enemy squad with minimum assistance from the player.
Boom, Headshot: Blacksite had a unique way of dealing with headshot damage. Instead of simply doing more raw damage, the game kept track of how many times an enemy had been shot in the head, and would insta-kill them after enough shots (2 shots for Iraqi soldiers, 3 shots for Reborn troopers). Headshots otherwise didn't do any extra damage compared to body shots.
Bag of Spilling: Blacksite was really bad about this, as no matter what weapons you were carrying, moving to a new chapter would often default you back to the assault rifle and pistol. This occurred even if the transition from one chapter to the next was literally simply walking from one end of a street to another.
Blatant Lies: In Blacksite, when you squad first encounters mutated human hybrids, Dr. Noa Weis dismisses it as "a congenital form of encephalitis". When you get attacked by a 40-foot alien worm, she explains it as a local "mutational effect". It's pretty clear she's not fooling anybody.
Break the Cutie: In Blacksite, during the prologue chapter Logan Somers comes across as the most rational and socially responsible member of the squad (granted, this is largely in comparison to Grayson, who's almost up there with Rico in terms of Ax-Crazy). By the end of the game after being tortured and experimented on by his own government, he's pretty much turned into an insane Omnicidal Maniac.
Conspiracy Kitchen Sink: The first game throws pretty much every popular government conspiracy element of the past century at you, especially if you collect and read all the optional info items.
Disc One Nuke: The BBG alien energy weapon you acquire about halfway through the game quickly replaces your assault rifle as the go-to weapon for most situations. It has infinite ammo, deals great damage, and also does increased damage against most of the game's bosses and special enemies.
Elite Mooks: The first game had Illuminati RedOps, who had red armor (of course) and acted as squad leaders over the regular Illuminati DarkOps soldiers. They were equipped with cloaking devices and did significantly increased damage with the assault rifle (and only the assault rifle, for some reason).
Everything Sensor: How you got new items and files in Area 51. Using it on your teammates would provoke different reactions from them; team joker Crispy would usually have something snarky to say.
Gameplay Ally Immortality: In both games your squadmates are functionally immortal until scripted to die in the game's plot. In Area 51 they were pretty much invincible, while in Blacksite they would be knocked down if their health was depleted, but would get up again after a couple dozen seconds or if the current firefight was finished.
Giant Mook: The Reborn Scouts in Blacksite serve this role; they've got average speed, but are well-armored and have twin energy blasters mounted on their shoulders. They're also about 9 feet tall, thanks to their huge robotic legs.
Guns Akimbo: Featured in Area 51, and done somewhat realistically: While you can pick up and use a second shotgun or assault rifle, you can't reload either of them until the magazines are empty, at which point you simply throw one of them away and continue using the other since reloading them both would be slow and clunky, if not downright impossible.
The Illuminati: Taking the role of your human (or non-mutated human, as the case may be) antagonists in Area 51.
Life Drain: In the form of flying parasites launched from your hands when in mutant mode.
Made of Iron: Your character in Blacksite can take an enormous amount of assault rifle fire before being critical injured, especially when compared to other similar games in the genre such as Call of Duty or Halo. You're more vulnerable on the highest difficulty, but can still survive a couple dozen bullets without needing to regenerate health, compared to only a handful of bullets for most other FPS games. Melee attacks and explosives will still end you fairly quickly, though.
Mook Maker: The Greys in Area 51 don't fight you directly, but rather constantly summon Illuminati soldiers to fight you while standing still inside a powerful energy shield.
Moon Landing Hoax: at one moment he would pass through a storage room holding a false lunar landscape, an Apollo capsule and some recording equipment. Bonus points for allowing you to shoot up the place.
If you unlock Dr Cray's third diary entry, he states that man has been to the moon but the Apollo footage was faked to hide what was really happening.
Dr Cray: The moon landings nearly four decades ago were part of a misdirection by our government to confuse the public regarding alien encounters. We've certainly been to the moon but the mysteries and horrors found there would never make for quaint historical quotation.
Obvious Beta: Blacksite suffers heavily from this, more so than probably any other mainstream shooter released in the last several years. The game can be completed, but just from playing a couple hours it's painfully obvious that it shipped in an unfinished state.
Second Hour Superpower: In Area 51, about 1/4th of the way through the game you gain the ability to transform into a mutant on command. As a mutant you have powerful melee attacks and increased speed, and time also slows down slightly (although not nearly as much as in games like Max Payne or First Encounter Assault Recon.
Self-Duplication: Mr. White, the Illuminati higher-up who serves as the Big Bad of Area 51, has made a few dozen clones of himself to help him administer the facility, resulting in a whole bunch of Mr. Whites running around the base. It's never really clear if you ever interact with the "real" Mr. White at any point in the game.
Silent Protagonist: In Area 51, Ethan Cole does have a lot to say in the between-level intermissions, but is completely silent during the game itself, including when interacting with other characters. Played completely straight with Aaron Pierce in Blacksite.
Shout-Out: In Area 51, on the studio site of where they filmed a fake moon landing, there's a lot of radio chatter in the background. One of thing things you may overhear is "What's your vector, Victor?"
Tron Lines: As ancient conspiracies go, the Illuminati has some sweet-looking glowing blue armor.
The Virus: The aforementioned biohazard that Ethan Cole was sent in to investigate, and the one responsible for the mutant outbreak. Blacksite has xeno-spores, a biohazard which turns Iraqi and later Rachel civilians into mutants very similar to the ones from the first game.
Visible Invisibility: In the first game, the Elite Mooks amongst the Illuminati soldiers are equipped with cloaking devices, but the Predator-style distortion effect they generate is so glaringly obvious that it barely makes a difference.
What Happened to the Mouse?: In Area 51, about 3/4ths of the way through the game you pretty much just abruptly stop hearing from your C.O., Major Bridges, without informing him of any of the crazy stuff you've discovered. Particularly notable as he was your only remaining ally at that point. Given that you end up vaporizing the entire Groom Lake region at the end of the game, it's almost certain he and all the other support personnel on the surface got blown up.