Half-Life Crossovers
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Dark Designs by Mr. Hybrid
After the end of the Combine Empire and Great Spirit Robot battle, Helryx takes a small group to explore a newly discovered underwater location. Whatever is down there isn't happy to see them and it's discovery changes everything about what was supposed to be a simple exploration mission.
Crossover - Half-Life & Bionicle - Rated: T - English - Adventure/Horror - Chapters: 4 - Words: 3,171 - Updated: 2/23 - Published: 1/27
After Aperture by Shius reviews
After everything she's been through, all the testing, mocking, and fighting with A.I.'s, Chell is finally free from Aperture. But what now? Without any knowledge of the outside world, and the war between humanity and the Combine, how will Chell survive? Follow the story of our favourite mute protagonist as she dives head first into the world of Half-Life, the world beyond Aperture.
Crossover - Portal & Half-Life - Rated: T - English - Adventure/Sci-Fi - Chapters: 12 - Words: 53,139 - Reviews: 44 - Favs: 54 - Follows: 86 - Updated: 2/23 - Published: 7/26/2013 - Alyx V., Gordon F., Chell, D. Rattmann
1920s Portal x Half Life by talietikasero
A 1920s double AU in which Aperture and Black Mesa are rival crime organizations, headed by Caroline and Breen respectively, and a night out turns into something unexpected
Crossover - Half-Life & Portal - Rated: K - English - Chapters: 6 - Words: 17,165 - Favs: 1 - Follows: 1 - Updated: 2/13 - Published: 8/25/2014 - Gordon F., Caroline, Chell
Brave New Earth by TheMadMadman reviews
Thanks to an alien artifact, beings from across the Multiverse begin to appear on planet Earth. However, there is a sinister force behind this chain of events, with equally sinister intentions. Some of these misplaced beings will become Earth's only hope, and some will become Earth's worst nightmare. NOTICE: Categories will change in accordance with franchises in latest chapter!
Crossover - DreamKeepers & Half-Life - Rated: T - English - Adventure - Chapters: 5 - Words: 22,084 - Reviews: 2 - Favs: 1 - Follows: 2 - Updated: 2/12 - Published: 12/19/2014 - Alyx V., Gordon F.
Life Crysis by Romulus98
The world united in its efforts to help the Vortigaunts fleeing Xen as refugees through portals successfully opened at Black Mesa. After forcing the portal to close, the Combine forced it back open. Thus began the war for the survival of the human and Vortigaunt race. Completely and most definitely AU.
Crossover - Half-Life & Crysis - Rated: T - English - Adventure/Sci-Fi - Chapters: 1 - Words: 1,938 - Favs: 1 - Follows: 2 - Published: 1/16 - Eli V., Gordon F., Alcatraz, Laurence Barnes/Prophet
Social Encounter by Weezel Soup reviews
She fought and struggled until she'd gotten out and she's made it through. She even got people that she could call friends, friends that need her to fight with them. It seems manageable because now, she isn't alone. That also makes it much harder. T to be safe and some language
Crossover - Half-Life & Portal - Rated: T - English - Adventure/Friendship - Chapters: 5 - Words: 9,469 - Reviews: 4 - Favs: 5 - Follows: 11 - Updated: 1/6 - Published: 6/28/2012 - Chell
And a Shepherd to Lead Us by A Very Thirsty Megalomaniac reviews
With the Earth ravaged by Combine negligence and xenian wildlife, the human/vortigaunt combined alliance takes to the stars. Commander Adrian Shepard (descendant of Cpl. Adrian Shephard, whose "H" was a casualty to history and poor spelling) sets to combat the new Reaper threat while shadow forces struggle to determine what humanity's future is going to look like.
Crossover - Half-Life & Mass Effect - Rated: T - English - Sci-Fi/Humor - Chapters: 23 - Words: 108,642 - Reviews: 69 - Favs: 116 - Follows: 129 - Updated: 1/1 - Published: 3/19/2014 - A. Shephard, G-Man, Shepard (F)
Dark Skies by CentuariAlpha reviews
Book 1 of 3. As ancient powers and enigmatic figures make their move, the stars will darken and the heavens will tremble as a scarred and battered humanity still reeling from the Combine occupation encounters the rest of the civilized galaxy.
Crossover - Half-Life & Mass Effect - Rated: T - English - Chapters: 9 - Words: 39,113 - Reviews: 268 - Favs: 334 - Follows: 424 - Updated: 12/31/2014 - Published: 2/22/2014
A Familiar Force by Jeggetts reviews
After defeating the Gene Worm Adrian Shephard thought it was his fate to be forever sealed in an endless void. However it turns out that someone has an... interest in the events that will take place on a world called Halkegenia.
Crossover - Half-Life & Familiar of Zero - Rated: T - English - Sci-Fi/Fantasy - Chapters: 8 - Words: 65,006 - Reviews: 59 - Favs: 131 - Follows: 148 - Updated: 12/25/2014 - Published: 9/16/2013 - A. Shephard, Louise
Sonic Opposing Forces by LegoMan7.62
My second fanfic and my first crossover idea I've just came up with involving opposing force and sonic satam, this is for those of you who read ANY half life and sonic fanfictions anymore, Please Enjoy, and Review at your own discretion.
Crossover - Sonic the Hedgehog & Half-Life - Rated: T - English - Adventure/Sci-Fi - Chapters: 2 - Words: 956 - Updated: 12/9/2014 - Published: 11/27/2014 - Sonic, Sally, A. Shephard
Semper Fi by Magnificent Bosh'tet
It's 1957. 90% of humanity is dead or worse. The planet is being frozen by a race of blood-thirsty, mutagenic, aliens. However, they didn't count on a HECU marine showing up.
Crossover - Half-Life & Resistance: Fall of Man - Rated: T - English - Sci-Fi/Horror - Chapters: 2 - Words: 1,228 - Favs: 3 - Follows: 2 - Updated: 12/8/2014 - Published: 11/21/2014 - A. Shephard, G-Man, J. Capelli
Half Dead by Pachy
Takashi,Rei,Saeko y su grupo intentarán sobrevivir a las criaturas alienígenas que llegaron a la tierra,pero no son su única amenaza...Zombies,Insectos Gigantes,Fauna Extraterrestre,pero están en la mira de la "Alianza"...
Crossover - Half-Life & Highschool of the Dead - Rated: T - Spanish - Adventure/Drama - Chapters: 2 - Words: 1,627 - Favs: 1 - Follows: 1 - Updated: 12/6/2014 - Published: 12/5/2014
Portal storms and Chipmunks by billboard018
Through one of Simon's latest inventions, Alvin and the gang find them self in a world struggling to survive in the aftermath of an alien invasion and are facing their biggest challenge yet.
Crossover - Half-Life & Alvin and the chipmunks - Rated: T - English - Sci-Fi/Adventure - Chapters: 2 - Words: 18,528 - Updated: 12/2/2014 - Published: 6/6/2014
MOCII - The Failed Voyage of the Borealis by Lagiacrus reviews
Sequel to 'The Misadventures of Caroline II'. When a Floppy Disk containing a challenge and information about the Borealis comes into GLaDOS' possession, she's willing to cross the sea to find out who dared challenge her. Caroline II is of course dragged along for the ride. But there's more to the Borealis than meets the eye - was its initial disappearance really an accident...?
Crossover - Half-Life & Portal - Rated: T - English - Adventure/Hurt/Comfort - Chapters: 4 - Words: 12,865 - Reviews: 18 - Favs: 12 - Follows: 13 - Updated: 11/3/2014 - Published: 8/8/2014
Universe's Crack by freakytiki34 reviews
Told to writes the fanfictions. Never writes fanfictions before. Here is crossover. Inspired by the works of Hanz Von Hozel. I still don't know what danube means.
Crossover - Half-Life & Firefly - Rated: T - English - Sci-Fi/Humor - Chapters: 1 - Words: 84 - Reviews: 1 - Published: 10/25/2014 - Gordon F., Kaylee - Complete
Non-Unified World Theory by AlmostVortal reviews
The Combine races to uncover the secrets of the Borealis with the Resistance on their tail. Little do either parties know (with the exception of a certain university professor) that the secrets it holds may change both the human world and the fantasy world forever. Two entities whom govern over both worlds must make their moves wisely, or prepare to meet unforeseen consequences.
Crossover - Half-Life & Touhou Project - Rated: T - English - Sci-Fi/Fantasy - Chapters: 1 - Words: 1,780 - Reviews: 2 - Follows: 1 - Published: 10/25/2014 - G-Man, Gordon F., Maribel H., Reimu H.
Half-Life The Convergence by deathwing17 reviews
A Council funded expedition into a previously unexplored system has gone horribly wrong. Now the expedition team find themselves stranded on a hostile world and hunted by a ruthless enemy. They soon join forces with a group of rebels hell-bent on freeing their home world and stopping a threat that could destroy all of galactic civilization. A threat known only as the Combine.
Crossover - Half-Life & Mass Effect - Rated: T - English - Sci-Fi/Adventure - Chapters: 6 - Words: 32,711 - Reviews: 48 - Favs: 86 - Follows: 108 - Updated: 10/22/2014 - Published: 9/12/2013 - A. Shephard, Alyx V., Gordon F., Liara T'Soni
Birth of the New Empire: The Attack by Fleetlord Atvar reviews
Approximately one year before what would have been the Battle of Yavin, the Universal Union of the Combine, now secure on Earth, set their gaze to the stars for more worlds to conquer. Probes have sent back images of a galaxy far away filled with new planets to bring into the Union. However, the Empire will not go down as easily as the Combine hoped.
Crossover - Star Wars & Half-Life - Rated: T - English - Sci-Fi/Suspense - Chapters: 2 - Words: 3,230 - Reviews: 1 - Favs: 2 - Follows: 2 - Published: 9/17/2014
A Chance Encounter by TheEndlessHorizon
On his way to White Forest, Gordon has a chance encounter with a certain someone. A certain Infinitely-Prolonged someone. (Rated T for language.)
Crossover - Hitchhiker's Guide to the Galaxy & Half-Life - Rated: T - English - Humor/Sci-Fi - Chapters: 1 - Words: 1,576 - Published: 9/17/2014 - Wowbagger the Infinitely Prolonged, Alyx V., Gordon F. - Complete
Half Life: Card Game Consequences by StupidSequel
The Combine have invaded Earth and after a friendship speech fails, Yami challenges them to a duel.
Crossover - Half-Life & Yu-Gi-Oh - Rated: T - English - Parody/Sci-Fi - Chapters: 1 - Words: 1,344 - Published: 9/10/2014
Epic Rattmann by UberVenkman reviews
Reawakened by a mysterious man in a suit fifteen years after he went into hibernation, Doug Rattmann faces the biggest adventure of his life when some vaguely human soldiers reactivate a certain power-mad AI...
Crossover - Half-Life & Portal - Rated: T - English - Adventure/Drama - Chapters: 7 - Words: 13,028 - Reviews: 13 - Favs: 7 - Follows: 15 - Updated: 9/3/2014 - Published: 2/17/2014 - G-Man, Alyx V., D. Rattmann, Weighted Companion Cube
Between Minds by 3theCaptain reviews
After surviving her battle with GLaDOS, Chell wakes in Aperture Science and makes another escape attempt. Meanwhile, after his ordeals through City 17, Gordon wakes at White Forest and tries to recover the Borealis and Judith Mossman... Or at least, that was the plan. The unexpected throws Chell, Gordon, Alyx, and Barney down paths toward inevitable consequences.
Crossover - Half-Life & Portal - Rated: T - English - Adventure/Drama - Chapters: 10 - Words: 79,430 - Reviews: 58 - Favs: 77 - Follows: 123 - Updated: 8/2/2014 - Published: 10/15/2011 - Alyx V., Gordon F., Barney C., Chell
Juste une minute de ta vie by Kurokami-Alice reviews
La Terre a été envahie il y a maintenant 10 ans par une puissance extraterrestre appelée 'Cartel'. La race humaine est à 90% éteinte, mais certains subsistent en étant sous le joug du Cartel et les résistants se battent pour vivre. Castiel est un jeune homme vivant avec son oncle dans Cité 17 et qui va voir sa vie changer suite à l'arrivée d'une étrange jeune fille.
Crossover - Half-Life & Amour Sucré - Rated: T - French - Horror/Sci-Fi - Chapters: 4 - Words: 13,355 - Reviews: 1 - Favs: 1 - Follows: 1 - Updated: 6/1/2014 - Published: 4/21/2014 - Alyx V., Gordon F., OC, Castiel
Chaos Cascade by MisterCereal reviews
Gordon Freeman, an average scientist working at the Black Mesa Research Facility, is in charge of handling the newest test subject; and odd green crystal-like object.
Crossover - Sonic the Hedgehog & Half-Life - Rated: T - English - Adventure/Sci-Fi - Chapters: 1 - Words: 487 - Reviews: 1 - Favs: 2 - Follows: 1 - Published: 4/27/2014
Always by TheEndlessHorizon reviews
In a realm of infinite worlds, there will always be constants and variables.
Crossover - Half-Life & BioShock - Rated: T - English - Mystery/Drama - Chapters: 4 - Words: 1,520 - Reviews: 5 - Favs: 3 - Follows: 5 - Updated: 4/16/2014 - Published: 11/14/2013 - G-Man, Robert L., Rosalind L.
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