The Ace: A brilliant scientist who was hired by one of the most prestigious research institutions in the world before the age of 30, quickly becomes expertly skilled in almost all conventional and unconventional weaponry despite no prior military or weapons training (other than a basic run-through on the use of MP5 in the Hazard Course), and consistently successful when fighting against overwhelming odds. When the Rebels have lost all hope and need an army to turn the tide, they look solely to Gordon. And he succeeds.
Action Survivor: Despite his legendary reputation come the second game, he was really just an Average (really smart) Joe minding his own business at a government job who was really good at adapting when the Incident happened. Even when he wakes up in the Combine era, he applies his resourcefulness despite not really knowing what's going on.
Assassin Outclassin': Following the Uprising and the creation of the Human-Vortigaunt Federation, the Commonwealth of Golmaran States and the Alliance of Nations, the Combine have tried to have him assassinate numerous times... all failed... it got to a point where Allied soldiers and even Allied heroes began placing bets how many assassins Gordan kills by the end of the First War, it was that common.
Asskicking Leads to Leadership: By the time of Uprising, he doesn't have any definitive rank in the rebellion, but he pretty much commands any rebel squads he comes across, who are all too willing to Zerg Rush a position if he so much as looks at it, all because he's good at killing things.
Badass Bookworm: He's a graduate of MIT with a PhD in Theoretical Physics; his doctoral thesis is ludicrously titled "Observation of Einstein-Podolsky-Rosen Entanglement on Supraquantum Structures by Induction Through Nonlinear Transuranic Crystal of Extremely Long Wavelength (ELW) Pulse from Mode-Locked Source Array". In laymen's terms... looking at teleportation effects on crystals when you fire lasers at them. Which suspiciously sounds like the experiment you are conducting at the start.
Badass Normal: Despite no prior military training or any superpowers, he regularly fights his way through highly trained special forces, augmented transhuman soldiers and super powered aliens.
Beware the Nice Ones: He's quite noble and heroic, and usually kind to the various security guards and rebels he meets on his journey. He's also killed about 1500 creatures, according to this post.
Bilingual Bonus: Possibly. Since he was in Innsbruck, Austria, he may or may not have learned German to communicate with Austrian students and scientists. Considering his intelligence and the necessity of German in Austria, it's heavily likely he did.
The Cameo: He pops up a couple of times as an NPC in the Gearbox expansion packs.
In Opposing Force, Shephard catches up to him just as he makes the jump into Xen.
In Blue Shift:
Gordon is in the tram right behind Barney's at the beginning of the game.
If Barney monkeys with the security cameras, he can see Gordon make his way to the lockers to pick up his HEV suit.
At the end of the game, Barney witnesses the HECU soldiers drag Gordon to the trash compactor due to a teleporter malfunction.
"'A previous hire has been unable--or unwilling--to perform the tasks laid before him...'" And he shows up again in the stinger—as the player character.
Child Prodigy: According to his original biography, he constructed a butane-powered tennis ball cannon at the age of six. He began his career in science very early in life; he's earned a PhD in Theoretical Physics, despite being only 27 years old at the time of Half-Life.
Color-Coded Characters: Orange. While it doesn't fit his personality very much, it ties in to the HEV suit's purpose: to provide safety in dangerous environments.
Cloud Cuckoolander: More than a few characters seem to think he might be something like this when they snark about his Heroic Mime nature (although they quickly drop this when its' clear he literally can't talk due to a defect in his brain), but one of the few hints of things he did before Black Mesa firmly lands in this territory when Alyx talks about old stories of how Barney and Gordon would race through the air vents when Kleiner locked himself out of his lab again.
Crowbar Combatant: He uses a red crowbar he found in a tool kit at Black Mesa as his melee weapon of choice, and is associated with it to the point he provides the trope image.
Deconstructed Character Archetype: For the standard First-Person Shooter protagonist like 'Doom Guy' and 'BJ' which had characterised FPS games up until the debut of Half Life. In Half-Life 1, Gordon Freeman isn't a badass supersoldier at the start: he was little more than a theoretical physicist of slightly above-average fitness who just happened to found himself at ground zero of a science experiment Gone Horribly Wrong which caused the whole mess. He had no real goal at first beyond just getting out of the facility alive and getting help, and only ended up becoming Humanity's last, best hope of stopping an Alien Invasion after he slaughtered his way through two armies (one of which is Human) and acquired enough firepower to do the job, and most of the time he did this out of self-preservation and protecting his colleagues. And being a scientist instead of a soldier, he relied as much on his wits as he did his arsenal of weapons to figure his way out of impossible situations as well as strategize how to best fight his opponents - and there are plenty of such obstacles and enemies around where he simply cannot defeat by running in guns-blazing like traditional FPS protagonists. And thank goodness Black Mesa just happened to develop the incredibly protective HEV suitwhich he wore and is filled to the brim with health and power stations/packs with which he could replenish/recharge his body health and suit power, as well as having many helpful security guards and scientists who are also trying to survive and working to end the catastrophe. And then, of course, there's that mysterious Humanoid Abomination in a blue business suit who keeps helping him out of tight spots for his and his 'employers'' own inscrutible reasons...
Dented Iron: Alyx shows his HEV suit (based on the half-life game) to be quite battle damaged, including a sizable hole in the torso's midsection with his bandaged body visible underneath.
Did You Just Punch Out Cthulhu?:
At the end of Half-Life 1, he takes down the Nihilanth, the Big Bad commanding the Xenian forces and a powerful being with god-like powers.
The Rebels' reaction when he takes down his first Strider, and in Episode Two where he takes out an army of them.
Divine Intervention: Well, more like "reality-altering shapeshifting alien intervention" — as much of a badass as Freeman is, there have been a few times where he could or should have died only for the mysterious G-Man to intervene and keep him alive for his own reasons.
Alternatively, the Vortigaunts believe he is guided by the Vortessence, acting as their savior and liberator, while Father Grigori seems to believe Gordon is watched over by God. The Resistance in general seems to view him as Divine Intervention, a messianic figure delivering them from the Combine, something Dr. Breen mentions in one of his speeches.
The Dreaded:
He steadily builds up a reputation throughout his adventures in Half-Life; by the midpoint of the game, the marines know exactly who he is and are actively hunting for him specifically. By the end, the Nihilanth is able to directly address him by name. Nihilanth: FREEEEEEEEEEEEEEMAAAAAAAAAAN...
By the second game, his fame has grown to such proportions that the mere sighting of him by Breen via accidental teleport hopping is enough to justify mobilizing the entire Combine Overwatch and yet they still underestimate him and get slaughtered in droves as a result.
Dude, Where's My Respect?: Despite being little more than an ordinary man fighting for his life with special equipment, Gordon's exploits throughout the series quickly earn him a legendary reputation. It often has more of an effect than he does by the time of Half-Life 2 and its expansions, with others’ accounts of him inspiring and rallying the Resistance long before and during his time as an active participant in their fight.
Expy: In a way, of Zane Zaminsky. Both Zane and Gordon are bespectacled scientists with trim beards who end up targeted by alien forces and government cover-ups, though Gordon deals with his set of problems in a considerably more direct manner.
Extremely Short Timespan: While the events themselves from the Black Mesa Incident, the Portal Storms, and the Combine occupation to Freeman's return, the global Resistance uprising and the fall of the Citadel occurred as separate events over a twenty year time period in-universe, due to being placed into stasis, from Gordon's perspective the events of Half-Life 1 and 2 all took place over the course of roughly five days.
Famed In-Story: Has become utterly revered by the events of the Golmar Uprising and he gains several names from the resistance.
Featureless Protagonist: Although Gordon has a consistent appearance in official art, as a playable character, there is no point where Gordon's appearance is portrayed or even mentioned. While Gordon has a 3D model in the original Half-Life and its expansions, he is a First-Person Ghost in Half-Life 2 and its episodes. This is finally averted in the ending of Half-Life: Alyx during the G-Man's speech, where he briefly shows you Gordon in-game, albeit in shadow.
Genius Bruiser: The guy who blows up (or beats down) every hostile Xen and Combine thing he sees happens to be a graduate of MIT, with a doctorate in Theoretical Physics no less.
Helmets Are Hardly Heroic: In promotional artwork, his HEV suit doesn't have a helmet, unlike those worn by the bodies of the other dead scientists found scattered around Xen. Whether this is the case in gameplay or not is something that the fans have disputed for decades. When the G-Man shows Alyx a vision of Freeman cloaked in shadow, he is clearly bareheaded.
The Hero: The scientist who thwarts two alien invasions and is also the central hope against the Combine for humanity and the Vortigaunts.
Heroic Mime: Unlike canon where its' vague as to why this is the case, in the Great Multiverse setting he's stated outright to be mute, due to a defect in his brain that prevents him from forming words, so every time he communicate he typically uses sign language to do so, or simply writing things down.
Hope Bringer: Gordon's incredible feats have inspired both humanity and the Vortigaunts to form La Résistance against the Combine. In fact, the Resistance members fight alongside with Gordon.
Icon of Rebellion: In the events of the Uprising, his exploits have made him an almost mythological figure to the Resistance.
Implacable Man: Gordon Freeman didn't really mean to save the world by slaughtering hundreds of soldiers and aliens at Black Mesa. They were just in the way of the exit.
According to Valve, this is played around with in the first game, where the player has the freedom to make Gordon either a typical action hero or complete psychopath, gibbing friends and foes with his crowbar while bunnyhopping through hallways. It's up to the player whether Gordon means well, is just trying to survive, or just wants to blow shit up. With the second game taking a more serious tone, they settled for making Gordon more of a straightforward hero.
Informed Ability: Gordon is a theoretical physicist, but the most technically complex things he does in the games are plug machinery in and solve rudimentary physics puzzles. Barney hangs a lampshade on that in the second game. Barney: Good job, Gordon. Throwin' that switch and all? I can see your MIT education really pays for itself.
Ironic Name: Gordon Freeman spends most of the series as a puppet of the G-man's machinations.
Irony: All his papers and the game manual info taken into account, Gordon's only been at Black Mesa for maybe some odd couple of weeks or so, and his resume inclines that he wrote a thesis about studying the effects of shooting energy at crystals; by all means, fresh MIT graduate or not he's a green-behind-the-ears nobody that got a special recommendation by Kleiner to be where he was at the definitive ground zero of the Resonance Cascade, bordering on Almighty Janitor since he didn't even know any bigger details of the project whatsoever and was little more than a hands-on chore guy for the experiment. And he was late to work, earning more than a few ribbings from his co-workers. And yet in spite of all of this, that "nobody" ends up defining himself as one of the deadliest beings on Earth.
Lightning Bruiser: He can take quite a bit of punishment, thanks to the suit, but can also run at ridiculous speeds and carry more firepower than the entire 2nd Armored Division.
Living Legend: As he was put into a status by the G-Man. Most of the resistance knew him through passed stories, until he was placed in City 17 after years passed.
Living MacGuffin: Eli and Alyx come to believe Gordon was the one being held in the Vault and set out to release him. Gordon is not the one in there, though.
Meaningful Name: The Resistance and Vortigaunts often call him "The One Free Man", the name serving as inspiration in their own fight for freedom.
Memetic Badass: In-Universe and out! virtually everyone in the wider multiverse still remembers him for his "unorthodox" use of a common tool, long after he has since stopped being a active part of fighting the Combine
Mike Nelson, Destroyer of Worlds: The entire Black Mesa Incident, specifically being told to force an alien crystal, that appeared out of nowhere, into the test chamber that led every bit of the planet down under. Oh, and he killed off the Load-Bearing Boss that was actively preventing the Combine from invading the planet.
Nerd Action Hero: Gordon is a theoretical physicist by trade, earning his doctorate before even pushing 30. He only becomes an Action Survivor due to a freak lab accident, and aliens and the U.S. military just wouldn't leave him alone.
Official Couple: With Alyx by the end of the Uprising and the creation of the Human-Vortigaunt Federation.
One-Man Army: While his suit is a big part of it (it gives him about 4 times as much health as a regular soldier when fully charged, can automatically reload his holstered weapons, and applies morphine and other assistance to keep him going at full strength even when badly wounded), it is still pretty amazing considering he is just a scientist. The best example is probably at the end of Episode Two. The rebel's main headquarters comes under attack from multiple directions. Dozens of Combine Elite Mooks storm through the roof on dropships and set up numerous defensive positions, a bunch of Hunters break in to support them, and a dozen striders, each supported by 2-3 Hunters, start attacking the base. After the rebel personnel is completely slaughtered, they just send Freeman, thinking that he's all they'll need to repel hundreds of heavily armed and armored dark energy rifle wielding super soldiers, and a bunch of giant tripod death machines supported by dozens of other, smaller tripod death machines. They're right. Completely.
Predictably most people in the wider multiverse are floored by what he was able to do and the fact that he's a regular ol' scientist and surviving things that often kills nearly anyone else, which he still shows this even after he actively tried to avoid situations that need him to fight but events outside of his controlled forced him to fight.
One Riot, One Ranger: The Resistance saw him as nothing short than an unstoppable god amongst men, and he's often sent into the fray alone or with minimal help — not because of Resistance laziness or cowardice, but because Freeman consistently wins and thrashes the Combine in the process single-handedly.
Powered Armor: His rechargeable HEV Suit, which provides damage mitigation, a Geiger counter, ammunition counter. The second game improves this by adding an Auxiliary power used for sprinting, oxygen monitoring, neurotoxin application, and a zoom-in feature like a binocular.
Red Baron:
Starts being called "The One Free Man" by the Vortigaunts and rebels.
"Anticitizen One" to the Combine, eventually he's labeled as "Priority Target N81".
The Axis eventually came to call him "Dr.Crowbar"
Right Man in the Wrong Place: The Trope Namer, as described by the G-Man, but not a straight example, because he's being manipulated by the G-Man.
Science Hero: Played With. According to the backstory, Gordon has an MIT doctorate in theoretical physics, but he doesn't use his scientific knowledge to save the day. Instead, he uses his intelligence to solve puzzles and his weapons (usually the trusty crowbar and Gravity Gun) to fight the bad guys. It doesn't help that Gordon and the other Black Mesa scientists unwittingly caused the Resonance Cascade, which is planned by the G-Man. Bottom-line: Gordon is this trope in-name and lore, but a straight forward Action Hero in-game, even if he accidentally messes things up.
Sell-Out: To one of Black Mesa's security guards. Gordon sported a ponytail at some point, and cutting it off - presumably to please management - earned him this title.
Slept Through the Apocalypse: He misses out on the Seven Hour War and subsequent two decades of Combine oppression, no thanks to the G-Man keeping him in stasis. G-Man: Wake up, Mister Freeman. Wake up and smell the ashes.
Specs of Awesome: Gordon wears a pair of eye-glasses and he single-handedly defeated a psychic Eldritch Abomination(although doing so caught the Combine's attention), a dreaded tripod, and an entire army of said tripods!
Took a Level in Badass: Before that fateful day, he was just a normal, if very intelligent, scientist working for Black Mesa. The moment he picked up that crowbar, though, he became an absolute force of destruction against the HECU, Spec Ops, Xen aliens and the Combine.
Training from Hell: His first combat experience saw him go from being a mild-mannered scientist to becoming an Action Survivor of a bloody catastrophe that left many of his friends and colleagues dead whilst pitting him against the United States government, hordes of savage monstrosities, and an entire extraterrestrial empire.
Underestimating Badassery: Breen hardly seems to think he poses much of a threat, given that he is just a scientist without formal combat training, and is rather surprised that the Combine Overwatch are having such a hard time fighting him. Dr. Breen: How could one man have slipped through your force's fingers time and time again? How is it possible? This is not some agent provocateur or highly trained assassin we are discussing. Gordon Freeman is a theoretical physicist who had hardly earned the distinction of his Ph.D. at the time of the Black Mesa Incident. The man you have consistently failed to slow, let alone capture, is by all standards simply that: an ordinary man.
The Voiceless: Implied. It's actually left ambiguous whether or not he can talk.
We Do the Impossible: From researching, developing and testing portals and teleporters, to saving the planet from two invading alien races that came forth from dimensions opened by said portals.
