Portal Stories: Mel

From the game's Steam store description:

Portal Stories: Mel is a community made, free modification for Portal 2 based in the Portal universe. It tells the story of Mel, who meets a new personality core and faces an undiscovered threat to the Aperture facility.

1952, in the early years of Aperture: Science Innovators, Cave Johnson’s scientists experimented with whatever they wanted. Not everything worked as it should have though, but that wasn't going to get in the way of the progress of Science! Mel unfortunately took part in a faulty test called the Aperture: Science Innovators Short-Term Relaxation Vault, falling asleep for years. When she finally wakes, there is a fake Cave Johnson telling her she needs to escape the facility and a new device called the Aperture Handheld Portal Device, her mind races with questions. “Who is this imposter Cave Johnson?” “What happened to the facility and its staff?”

"What happened to me?"

Tropes used in Portal Stories: Mel include:

• A.I. Is a Crapshoot: AEGIS, naturally, though he's only trying to terminate you and Virgil (and GLaDOS) because he perceives you as a threat.
• Ambiguously Gay: Virgil is obviously crushing on the Rainbow Core. He's downright Adorkableabout it.

Virgil: Er... er... did you... eheh... by any chance... er... get that core's serial number? I... I.. I'm... er... I'm asking for... a... a-a friend, yes, a friend.

• Anachronism Stew: Parodied. While masquerading as Cave Johnson, Virgil mentions that recent earthquakes have shook up time and brought in things from the future, to try and explain why the building has been updated since Mel was asleep.
• Antepiece: Very early in the game you are instructed to put out a fire by portaling water onto it. This comes in handy in the final level.
• Arc Number: 2056.
• Blatant Lies: When Virgil is pretending to be Cave Johnson. He stops because he decides Mel's not stupid enough to fall for them.
• Book Ends: The game starts with Mel entering the Aperture Science Innovators Facility and descending down into the depths on an elevator. It ends with her ascending a different elevator and exiting through the remains of the same facility.
• City with No Name: The Michigan town which holds Aperture; justified as the company built it themselves.
• Company Town: The town is built entirely by Aperture for the purpose of housing its employees.
• Continue Your Mission, Dammit!: Virgil is constantly telling you to hurry to avoid the rising goo, except you have infinite time, and you never even see the goo rising behind you.
• Cryonics Failure: Mel was only supposed to in suspension for a brief period of time to test out the relaxation vault. Guess what happens.
• Desolation Shot: There is a truly beautiful one in the final cutscene that pans out to shows the exterior of Aperture Science amidst the ruins of society.
• Evil Sounds Deep: Not that AEGIS is "evil" Per se, but he has an unsettling creepy voice that fits his antagonistic role. This contrasts starkly against his logical, computer-like personality.
• Foil: AEGIS is in many ways the exact opposite of GLaDOS. He acts far more like a non-sentient A.I. (whereas GLaDOS acts very human) and never talks to the player or Virgil directly. Rather, his dialog is more of an announcement of whatever he is detecting and what he is doing.
• Foreshadowing: When AEGIS detects Virgil and Mel in the facility, he notes that there are three targets. The third target is eventually revealed to be other than GLaDOS, but AEGIS was shut down before it could destroy her.
• Fun with Acronyms: AEGIS, the Aperture Employee Guardian and Intrusion System, and the antagonist of this mod.
• Game Mod: Of Portal 2.
• Getting Crap Past the Radar: While looking through old emails in Aperture's archives, Virgil comes across one that explains how to "Increase the size of your core in two easy steps". Guess what "core" is an obvious euphemism for.
• Giant Spider: AEGIS resembles one. He even hangs from the ceiling like GLaDOS.
• I Have This Friend: Virgil asks if Mel got the Rainbow Core's 'serial number'... for a friend, yes! A friend!
• Interquel: The game is set sometime after the first Portal, and ends with AEGIS draining the facility's reserve power and waking up Chell, setting up the events of Portal 2.
• Man of a Thousand Voices: All characters excepting Virgil (i.e. Cave Johnson, AEGIS and "The Rainbow Core") are played by one person, Harry Callaghan.
• Meaningful Name: In The Divine Comedy, Virgil was Dante Alighieri's guide through Hell and Purgatory. Here, Virgil is acting as Mel's guide through the Aperture Science Enrichment Center, so really the only difference is that Virgil's a core here.
• Morton's Fork: In one area, you have a choice of either the stairs or an elevator to get to the sphere exit as the sphere itself begins to flood/fall apart. Virgil will berate you no matter which you choose, as both are risky.
• Mythology Gag: The game's stinger features a long, winding flythrough of the Aperture facility, much like the stinger of the first portal.
• Nice Job Breaking It, Hero: When Mel goes to shut down AEGIS, she and Virgil notice that one of its targets, alongside the two, was GLaDOS. However, while them shutting it down allows her to get back online, the shutdown sequence also reawakens Chell from extended relaxation.
• Ooh, Me Accent's Slipping: In-Universe. Virgil impersonates Cave Johnson's voice when you wake up from the Relaxation Vault and you may or may not notice this immediately. As you progress through the facility, however, his voice starts to fluctuate to his natural accent and he looses Cave's accent altogether just before he decides to come clean.
• Rip Van Winkle: Thanks to the Aperture Science Innovators Short-Term Relaxation Vault.
• Scenic Tour Level: The game begins on a train traveling through 1950's Aperture Science.
• Shout-Out:
  • The game starts off with Mel arriving at Aperture Science on a tram.
  • A few shout outs to The Maze Runner, there is a scrawl that says WCKD is good, In the end elevator the number 71526483 is seen which was the escape code to the film version of the maze, the design of the exterior of destroyed Aperture is also based off the Maze
• Sports Hero Backstory: Mel was a participant in the Nuremburg Olympics, as she joined Aperture back when they used these, war heroes, and astronauts as test subjects.
• Story Difficulty Setting: Story Mode completely overhauls the campaign, making the puzzles less challenging. It was created as a response of feedback claiming that the game was too hard, making it hard to follow along with the story.
• Super Drowning Skills: Even referenced in an achievement for drowning.
• Thanatos Gambit: AEGIS uses its last seconds before it shuts down completely to wake Chell, trying to finish off GLaDOS once and for all.
• Time Limit Boss: Just like in the last two games, the only difference being oxygen depletion rather than neurotoxin.
• Token Good Teammate: Virgil is the only artificial intelligence in Aperture Science who's both completely functional and helpful, either in the mod or the game proper.
• Violation of Common Sense: Several achievements, including some hidden ones, require you to die in some way. While only one requires falling for a trap, the others are rather easy to avoid (though not impossible to do by accident.)
• Wingding Eyes: Virgil's eye is based off of the 1970s Aperture logo.