Ambidextrous Sprite - Characters like Sol and Ky can easily switch to the other hand, but those with asymmetrical costumes (Testament, Venom) or missing limbs (Baiken) are a bit harder to justify. Xrd, a 3D game whose visual design is centered around replicating the feel of 2D, intentionally uses this trope.
And Now for Someone Completely Different - Overture drops nearly all the bounty hunters, and instead focuses on the story of the Gears. Of all seven playable characters, only one is a normal human (Ky).
Art Evolution - Sol's hair has gotten much, much spikier since the first game in the series. There's a few other changes as well, such as Axl becoming less muscular and Testament becoming (marginally) less feminine.
Awesome, but Impractical - Instant Kills. Sure, they end the round automatically if they connect, but most are seriously difficult to hit with. If they know it's coming, it's damn near impossible, unless the opponent is stunned. In that case it's somewhat doable.
Or you're playing the first game or using "Generations GG Mode" in Accent Core, in which case IKs are basically Quick Time Events.
Justice's Gamma Ray Overdrive. Possibly the most damaging super in the game, but it has a painfully long windup time and burns a full meter, the former only mitigated slightly if you're at close range (where the opponent runs risk of being snared by Justice's electrical discharge before the beam fires).
Order-Sol's Dragon Install: Sakkai Overdrive plays with this. If pulled off in its entirety note Gold O.Sol's version of the Overdrive is an autocombo and the final hit (the original GG1 Tyrant Rave) is guaranteed to kill, Sol's string of attacks will cap off with his Napalm Death IK, effectively ending the round on the spot. The problem? Aside of the requirements for activating the super (full Tension andLevel 3 Charge prior to Plus R, where it only consumes 50% Tension like most other Overdrives), there's a good chance that the opponent will already be done for by the time Napalm Death comes out.
Sol's DragonInstall Overdrive in the same game has its own theme, "Ride the Fire", sounded off with a Metal Scream of "LET IT OUUUUUUUUUUUUUUUUUUT!" Even after Dragon Install wears off does the music continue until the end of the round.
Badass Army - The Servants in Overture, and they come in different types.
While we only see/hear of the efforts of the main players (i.e. Sol, Ky, Kliff, and Justice), both the Gears and the Holy Knights count, seeing as the Crusades lasted over a century and probably would have continued on longer had it not been for Justice's sealing (indeed, in the Bad Future, the Crusades continue on for at least another eight).
One shown in an XX drama CD, where Ky's death results in a future where Dizzy takes over for her late mother as the leader of the Gears, and most of the cast dies by the end. Thankfully, I-No, spurred on by That Man, saves Ky for her own interests, bringing a much more positive end to the Crusades.
I-No's stages take place in future Babylon, on top of a ruined cathedral in XX and on the abandoned city streets overrun by wolves in Xrd. Also, in the latter stage you can spot the former stage in the distance in the right corner.
Battle Intro - As usual for fighting games, each character has pre-match intros, and several have special intros against each other, most notably Sol vs. Ky and Millia vs. Zato. Also, several fights in Story Mode have intros that actually have an effect on fight itself.
Beat Them at Their Own Game - Realizing that the solution to the Gear problem wasn't more Gears (a lesson likely learned when Testament went rogue thanks to Justice's powers), the Post-War Administration Bureau sought to create an anti-Gear weapon derived from Gear technology, resulting in the parasitic/symbiotic Forbidden Beasts. Gears instinctively know that Forbidden Beasts are their enemies, explaining the nostalgia Testament and Dizzy feel around Eddie, and Eddie rationalizes during AC+ that a Gear's body would be able to sustain him better than Zato's did due to the similarities in physiology.
Big Bad Duumvirate - The United Nations' Senate and Ramlethal Valentine are in the alliance of convenience in Xrd.
Bloodless Carnage - Guilty Gear XX Accent Core has the blood removed for some reason.
Bullet Time - All Roman Cancels in Xrd (Red, Yellow, and Purple) briefly cause time to slow down for everything but the character who initiated the RC.
Capcom Sequel Stagnation - Guilty Gear XX has seen four "special edition" rereleases so far (with yet another one slated for summer 2012), though each version does add to the complexity of the game.
Cel Shading - Xrd uses this to emulate the 2D look, further enhanced by the deliberately choppy animation.
Central Theme - The plot revolves on moral and religious concepts like innocence, guilt, justice, hope, atonement and life; not just on individual lives, but on a bigger, fictional picture.
Combo Breaker - The Counter Burst. note These, however, are unavailable when your character is staggered, being thrown (command grabs included), dizzied, or hit by an Overdrive (indicated by an X covering the gauge). The Burst Gauge slowly refills over the course of a battle as you deal and take damage, and a successful Blue Burst leaves you with 30% of the gauge intact. Their biggest drawbacks are that they're punishable on block and if you whiff/the Burst is blocked, your Burst Gauge drops to 0%.
Damage-Increasing Debuff - Negative Penalties, incurred for repeatedly retreating from the opponent and not attacking, make the character susceptible to taking more damage in addition to emptying their Tension Gauge and minimalizing any Tension gained for a time after.
Damn You, Muscle Memory - Besides the usual edition transition troubles, Xrd in particular gets this because of the major changes to the Roman Cancel system and being based on #Reload, four editions before AC+R and the last one Daisuke Ishiwatari had a direct role developing before switching his attention to Overture.
Death or Glory Attack - Instant Kills, you either have one connect and win or miss/is blocked and you lose your Tension bar. Add to the fact that they can't combo and it's easy to see you don't see them used often in Tournament Play.
Despair Event Horizon - Not just one person experienced this, but the whole Holy Knights and also the world when Ky Kiske died in the Battle of Rome in the alternate timeline. The event is referred as "the day where the hope of the world crumbled."
Easter Egg - Certain characters (Sol/O.Sol, May, Millia, Baiken) have more than one Taunt and/or Respect gesture. These aren't character-specific, though.
In AC (and its revisions), the elderly painter in the new London stage will occasionally paint a scene depicting an alien instead of an unfinished still of the stage itself. Seeing this in the 360 version of AC+ or Vita version of AC+R nets you a trophy/achievement (Close Encounters of the 3rd Kind).
Eldritch Location - The Backyard, a realm which contains an immense amount of information within, and the source of the series' magical energy. Those who enter the Backyard risk being crushed by the sheer amount of data inside it.
False Flag Operation - In Overture's aftermath, a few days after Ky proclaims his intentions to seek co-existence with the Gears, Illyria suffered new raids from the Gears. Sol states that someone is manipulating the Gears to disrupt Ky's plans.
Fantastic Aesop - Don't tamper with genes and turn creatures into magical weapons of war... because they will wipe out the Japanese.
Final Boss - An uncommon case among most fighters in that every final boss in the main installments (including X and XX) has been a woman. In order, they are Justice, Dizzy, I-No, Valentine, and Ramlethal Valentine. For bonus points, they all share an at least tangential connection with one or more of the other characters on that list. Spin-offs Isuka, Dust Strikers, and Judgment break this convention with Leopaldon, Gig, and Judgment, though Gig half-subverts it (he has a formerly human maiden sticking out from his lower body).
Finishing Move - Instant Kill attacks are specific to each character and end the round, regardless of how much health the opponent has.
The first game's Instant Kills ended the entire MATCH on the spot if they went through.
Force And Finesse - Sol utilizes a rough, unpolished, "all guns blazing" style of combat and wields a blunt sword with no visible edge. Ky favors precision and, having been properly trained in the art of swordfighting, brandishes a longsword.
For Want of a Nail - In one of the drama CDs. In the original timeline, Ky dies. And his life is pivotal to the whole war. Needless to say, the war went on even after Justice died because Dizzy took up Justice's role in the rebellion. It was eventually I-No, who met That Man and decided to save Ky's life, resulting in the current timeline.
Freeze-Frame Bonus - As of Xrd, several characters have tiny inscriptions on parts of their outfits, such as "A merry heart doeth good like a medicine" written on the back of Faust's coat and "Settle With Elegance" engraved on Venom's glove.
This was also the case in Overture, such as the "Nonsugar" engraving on Valentine's sleeves and the words "Proteus" and "Universe" adorning That Man's robes in a multitude of spots, as well as the phrase "Heven Made Men For Its Reason, Men Respect Men For Their Own Sake" scribbled on their back coattails.
Functional Magic - Guilty Gear 2's lore and plot explain the source of all magic: The Backyard is a dimension that contains the universe's laws of physics, where they can be temporarily tweaked and defied on Earth to suit the desires of humanity.
Gaiden Game - Canonically, the X and XX series are these. They're very much in-canon, but are largely inconsequential to the events of Overture (unless your name happens to be Sol, Ky, or Dizzy), which was touted as the real continuation of GG1 and second "main" game in the series (with Xrd being the third, hence the name).
Genetic Engineering is the New Nuke - The Guilty Gear universe is an aftermath of the said scientific (magical) innovation. Gears are biological weapons that were powerful enough to stand against humans for a hundred years and had almost pushed humanity into extinction in the drama CDs.
Genre-Busting - Overture. It combines Hack n Slash with Real-Time Strategy, and is inspired by DotA, albeit with much greater control over armies. The fighting game mechanics from previous entries remain intact on top of this, best seen when two Master Units (i.e. Sol, Valentine, Raven, etc.) face off against one another.
Genre Shift - The series underwent an experimental phase while in the midst of tweaking XX. Isuka's GG Boost Mode and the entirety of Judgment were Beat Em Ups, while Dust Strikers was a Platform Fighter in the vein of Super Smash Bros. The first true sequel, Overture, was equal parts RTS and H&S. The next proper installment, Xrd, will return to the series' roots as a 2D fighter.
The "SLASH!" that punctuates a KO may qualify, given that it doesn't matter what kind of attack lands the finishing blow.
Great Offscreen War - The Crusades. There has yet to be a game that covers the apocalyptic, over a century-long event in full, though certain characters' stories in XX and AC+ offer a glimpse of the war's final years and the XX drama CD shows what would happen if Ky were to die during the Battle of Rome in 2173.
Hit Stop - Trope Namer. In this case it's used for gameplay purposes: when a character gets hit, the short pause in animation allows the player to react to it and confirm into a combo. Scoring a Counter Hit increases the pause even more.
Xrd has a feature known as Danger Time, triggered randomly by a clash of two opposing attacks, where a successful hit off of canceling the clashed attack will cause a Mortal Counter, a special type of Counter Hit with even longer hit stun that can also be canceled into any other type of attack.
Humans Are the Real Monsters - Gears were originally intended to be the next step in human evolution, hence the name "Gear." Instead they were weaponized, with Sol being made into a Gear against his will.
Idle Animation - Several, from Sol cracking his neck to Slayer tugging at the collar of his shirt to Venom chalking up his cue. Xrd adds more, like Ky waving around his blade in a circular motion for a bit (presumably to keep his sword arm loose and limber) and May stretching a few times before striking a cute pose.
Immortality Begins at Twenty - Seems to be the case for the Gears (the humanoid ones, at least), who already exhibit vastly accelerated aging processes and are functionally ageless. Once they hit physical and mental maturity or were already in their prime when converted, they stop aging and remain in their current state indefinitely. For example, Testament appears to be in his twenties despite being at least three times that old and the 170+ Sol looks no older than when he worked on the Gear Project back in the early 21st century.
Internal Homage - The promotional artwork/cover art for Xrd (the page image above) is meant to call that of◊ Guilty Gear X to mind: the bottom character is holding chains, the top one is brandishing their sword. The main difference is that Sol and Ky's positions have been swapped.
Invulnerable Attack - Gold Bursts, while best known for their ability to instantly max out your Tension gauge if they successfully connect (and if they don't, you're given 30% of your gauge back as reimbursement), are also invincible against all other attacks (including another Burst). Used wisely, they make for a good offensive and defensive tool. Several Overdrives additionally feature start-up invincibility.
Jump Physics - Everyone can double jump, save Chipp, who can triple jump. In addition, there are mid-air dashes.
Justice can both triple jump and triple air dash. You can only imagine what that kind of mobility, combined with superior offense, defense, and attack priority compared to virtually every other character in the game, spells out for her as a character.
Sadly, Justice's rebalancing in Plus R left her without her triple jump and any air dashes unless she performs a specific full-Tension Overdrive (Omega Shift), and even then it's temporary.
Kliff stands out in that his jumps are extremely floaty, much like those of Dhalsim or Anakaris. In AC+R, however, this was severely toned-down as part of his rebalancing.
Ki Attacks - Pretty much everyone from Asia, which is part of why the surviving Japanese are so highly valued.
Lag Cancel - The Roman Cancel technique, which allows you to cancel the animation of nearly every move of the game provided that it connects with your opponent on hit or block and you have at least half meter.
Exclusive to Order-Sol is his ability to cancel his ground normals with his Charge animation and then cancel that into another normal and so on and so forth. To succeed, fast, brief inputs are necessary.
Launcher Move - Dust attacks. They also happen to function as overheads and put the opponent into a helpless state for a short period of time. In Xrd, characters can also chase horizontally after their opponent, who will instead go flying sideways and careen into a wall.
Leitmotif - With the exception of Guilty Gear Isuka (unless you count "Holy Orders?" for Robo-Ky) and rivalry-specific themes, each character has their own distinct tune when fought. Most have been consistent since GGXnote of the original cast, 7 of the game's 13 fighters (Sol, Ky, Millia, Chipp, Baiken, Kliff, and Justice) retained their original themes in later titles and XX even brought back "No Mercy" (Sol vs. Ky) and "Still in the Dark" (Millia vs. Zato-1/Eddie) from the previous game for when the EX versions of the characters face off.
Surprisingly, Xrd does away with all of the previous character themes (even longstanding ones like "Keep Yourself Alive") for a new batch of individual tunes, aside of Ky (see Background Music Override) and Ramlethal Valentine (who gets a remix of "Diva" from Overture, the previous Valentine's theme).
Limited Animation - Subverted in Xrd. The entire game is rendered in cel-shaded 3D, but the characters are not animated as smoothly, thus invoking the look and feel of the previous 2D games in the series.
Magic A Is Magic A - Buried in Magi Babble is many rules and guidelines of how magic was discovered and how it's used in the Guilty Gear universe, such as the Twelve Steps and the Backyard from which the world's "source code" can be played with to create magic.
Magic from Technology - Magic in the GG verse is a perpetual energy source discovered through the fruits of science. Curiously, Ki is grouped in here as well, labelled as the fifth and least-known of the five elemental categories of Magic. The Post-War Administration Bureau theorizes that its prevalence in Eastern cultures may be due to their genetic makeup and deeply spiritual nature.
Magic Genetics - Human magic users mostly sidestep this as they were the ones who discovered magic in the first place and have to follow complex rules in order to use it. The Gears and Backyard residents, on the other hand, seem to exist specifically to disregard the scientific laws of nature, and stylishly at that.
Magic Knights - The members of Sacred Order, Sol and Ky included.
Mechanically Unusual Fighter - Robo-Ky has to manage two different meters. One is a thermostat, which builds up as he fights and can only be vented via a certain command or risk a damaging explosion. He also has a power gauge which, unlike everyone else, cannot be charged conventionally and can only be charged via a laid-out power mat or his command grab. His special and Overdrive attacks drain from this power gauge.
Order-Sol is a downplayed example (and borderline subversion), possessing a Charge Meter that improves his specials and Overdrives as he gains levels. Using his specials will drain a fair amount of meter (though the drain rate was decreased in AC+R), which will then need to be recharged. While it is certainly possible to use O.Sol to deadly effect without charging up, players who can properly manage his level of charge—which includes using Action Charge note pressing D after any special aside of Charge and Charge Burst to restore a portion of his meter and his ability to "Charge Keep" note using the Level 1 versions of specials instead of the Level 2 or Level 3 ones by inputting D along with the specific command; Gun Blaze is the sole exception, as the directional input overlaps with Charge's—will literally get the most bang for their buck.
Xrd newcomer Elphelt is an oddity among the entire cast in that she relies heavily on guns to keep opponents at bay, wielding a shotgun and a sniper rifle. Players have to enter a specific command to have Elphelt line up her shots and then have to manually aim before firing. Unless a reload command is input, Elphelt will immediately stow away her weapon until its next use.
Mirror Match - Even has three theme tunes for this: "Fatal Duel", "Nothing Out of the Ordinary" and "Ditto!"
Mohs Scale of Science Fiction Hardness - Level 2. The rules of magic are noted in complex, painstaking detail, but rigid and consistent, with all subsequent applications falling within the realm of pre-established plausibility. The fact that the core concepts of magic in the GG verse are rooted in music theory may have something to do with it.
Monster Lord - The Command class of Gears. So far, all known members of this category are female, paralleling queen ants/queen bees, with Justice in particular embodying several Hive Queen traits.
Nintendo Hard - Some of the missions in the series can be incredibly frustrating due to overwhelming odds stacked against the player, e.g. Mission 50 in Guilty Gear X2/Mission 100 in Reload, Normal Ky at 50% Health and poisoned vs Gold EX Sol with regeneration.
Note that Gold Sol already has regeneration and boosted speed and attack. His attack and speed is boosted even further because he's in permanent Dragon Install.
Non-Lethal K.O. - With the exception of Kliff and Justice in the original Guilty Gear, after each battle every single character seems perfectly all right and usually capable of speech, even if the battle ended with an Instant Kill, which appears to end in death. (This includes Faust's in GGXX, which looks like he set off a nuclear bomb, Bridget's, which launches the opponent into the moon, and Slayer's, which apparently launches the enemy out of the galaxy.)
Open Secret - The creators provide many examples of this. From the way the series progressed, secrets are revealed and by the rational mind of the audience, some things are just too obvious even if they aren't officially declared yet.
An example is Faust being a reformed Dr. Baldhead. It's never been explicitly stated, but come on, how many nine-foot-tall doctors wielding giant scalpels can there be?
Player Mooks - The various Servants in Overture avert this, each character's Tribe having several individualized and role-specific units designated as either Minions, Standard Servants, or Elite Servants, with the twist that they're physical manifestations of their Master Units' souls.
Power at a Price - The Forbidden Beasts are named so for a reason. In order for a human to properly fuse with them, the host must first offer up something in return. Zato sacrificed his eyesight for Eddie, but what Millia unwillingly gave up to obtain Angra when taken in by the Assassin's Guild remains unknown. That's not all, unfortunately; as time goes on, the Forbidden Beast will slowly eat away at its host's mind and eventually kill them, as seen with Zato's eroding sanity and eventual death (although Eddie claims to Millia it was not his intention). This problem is the cornerstone of Millia's Accent Core Plus story, as she grapples with Angra's murderous thoughts and fears she'll share Zato's fate once the magic in her hair fully awakens.
Power Trio - Has some of these, though characters are more complex than their representations:
Sol Badguy: Lazy, unpredictable, seeks revenge and atonement by wanting to kill all Gears and That Man (Id)
Ky Kiske: Law abiding, loyal to the authorities, workaholic, religious (Superego)
Dizzy: Pacifist, gentle, innocent, loyal to her friends (Ego)
Necro: Violent, hates humans, takes over his master (Id)
Undine: Protective, peaceful if Dizzy isn't threatened (Superego)
Dizzy: Pleads the two to stop fighting (Ego)
Zato: Desires power, revenge, lusts for Millia (Id)
Venom: Loyal to the Assassin's Guild, loyal to Zato, seeks Millia not just for revenge (Superego)
Millia: Quits the Guild because of her conscience, seeks peace by destroying it and killing Zato (Ego)
Raven: Extremely loyal to That Man, has no other alliances (Superego)
That Man: Seeks atonement for what he has done, has mysterious plans to save the world but regrets his actions (Ego)
Baiken: Seeks revenge, bloodthirsty, short tempered (Id)
Chipp: Determined to become president, follows a ninja's honor (Superego)
Anji: Laid back and relaxed, friendly and optimistic, desire eternal youth (Ego)
Panty Shot - Let's just say every fighter wearing a skirt and leave it at that. This includes several of the men.
Press X to Not Die - How to avoid getting IKed in GG1 or GGAC if Generations GG mode is active.
Puzzle Boss - Many of the missions in XX. One particularly notable example: you have to defend against an invincible, high-level A.I. I-No for 40 seconds, when your character is incredibly weak (Bridget), has half health, and is also poisoned.
Rule of Cool - When your playable cast includes a blind assassin who kills people with the monster living in his shadow, a girl who shoots laser-spitting piranha fish out of her wings, and a ninja, and this barely scratches the surface, you can only be dealing with this trope.
To put it another way, one of the playable fighters is a kusarigama-wielding fire user from England who involuntarily slips back and forth through time. He is quite possibly the most normal member of the cast.
One can also reminded about a certain messiah when Dizzy's identity is examined. She is called the "hope of the world beyond my expectations" by That Man, celebrates her birthday on December 25th, has 12 female friends in the Jellyfish and has a dual nature by being both Human and Gear...
Scenery Gorn - The GGX trailer, parts of the manga and the AD 2173 stage.
Other qualifiers include the Graveyard (the stage Kliff is associated with), Hell (particularly in AC), Babylon (I-No's non-boss stage in XX, which still manages to qualify as regular ol' Scenery Porn) and the Ruins of a Castle stage from GG Boost Mode in Isuka.
The backdrop of the final battle in Xrd is none other than the ruins of Japan. All prior story material tells you that Justice annihilated it, and make no mistake, the claim is no exaggeration at all.
Scenery Porn - Although the world suffered heavily as a result of the Gear attacks, the various locales you see in-game do a good job of showcasing its remaining beauty, both natural and man-made. Stages in X, XX/AC, and Isuka like Russia, China, London, and the Japanese Colony are breathtaking, and even more otherworldly places like the Grove, the Phantom City, and Kingdom Cemetery have their own charm.
To say nothing of the backdrops in Overture. The Gear utopia (and island paradise) Ganymede comes leaping to mind.
Xrd looks set to continue the trend with equally colorful and vibrant destinations, both returning and new.
Schizo Tech - Despite the series taking place in the late 22nd century, most real life countries and cities (London, Paris, Russia, China) appear not too far off from their present-day counterparts, and Illyria (a conglomeration of various European states) and Ganymede (an archipelago settlement founded by the refugee Gears) are no different presentation-wise (though the latter has a slight Atlantean vibe to it). Zepp, being the only nation to preserve Black Tech as opposed to outlawing it, is decidedly more futuristic than most spots seen, though its heavy urbanization and focus on machinery makes it the Floating Country equivalent of a City Planet; some stages, like the ones in X/XX, have certain parts of Zepp's several islands looking no better than dumps and deserted construction sites. What's left of New York City in A Country, on the other hand, looks to have regressed to an Old West feel after extensive rebuilding by the time Xrd rolls around.
Science Is Bad - Technology is branded as "Black Tech" and is banned for destroying nature. People used magic instead but eventually, also abused it.
The existence of Vitae in the Lightning the Argent novel (if you factor out the potential for Body Horror if a Commander Gear stirs up the dormant Gear cells used) shows that all of the research put into the creation of Gears wasn't inherently bad. Trying to weaponize them, on the other hand? Not such a good idea.
As of AC+, Anji may have became a villain. Though that ends up subverted that after one direct look at Baiken, and he called it quits and rejoins Baiken.
Sequel Number Snarl - GG2: Overture avoided this by merit of regulating the X series to the status of sidestories to the original game without diminishing their impact on canon. Xrd, which could essentially be considered a sequel to both XX and Overture, oddly picks up the slack, however, as it more or less continues on from the titling conventions of X and XX (Guilty Gear X3 would've been an acceptable choice, but ASW certainly couldn't call the game "Guilty Gear XXX", now could they?).
The Seven Mysteries - Of the 8 Jinki from the Outrage set, only 4 of them are shown: Sol's Fireseal/Fuenken, Ky's Thunderseal/Furaiken, Anji's Zessen, and Slayer, who has a dagger which can cut through Forbidden Beasts.
Likewise, this is suggested of the aforementioned Forbidden Beasts, also known as the "Six Forbidden Magics." Only two, Eddie and Angra (the fifth and sixth organisms according to supplemental materials, respectively tethered to Zato and Millia), have been seen so far, with Venom being a third test subject for the bonding process who was rejected when his body was deemed unsuitable as host material.
Snap Back - Many characters' movelists in Xrd omit the newer moves from Accent Core and its revisions, returning them to their #Reload state. In turn, some of the tactics that had been patched out, such as Sol's dreaded Dust Loop, are back in full force.
Soundtrack Dissonance - Faust's Instant Kill in Xrd starts with the usual Instant Kill theme, then cuts away to Beethoven's "Ode to Joy" as he operates on his hapless victim.
Stylistic Suck - Of a sort with Xrd, pertaining to the 3D models and not the art direction. First they made the 3D models and recorded the individual moves. After that they applied filters and effects such as motion blur that you couldn't get with just 3D. Finally they bumped down the frame rate to emulate classic 2D sprite movement. The end result is technically choppier, yet due to fighting game sensibilities actually looks better.
Super Move Portrait Attack - In Xrd all characters have one Overdrive, like Sol's Tyrant Rave and Ky's Ride the Lightning, that has a special animation of the character preparing to dish out the pain. All other Overdrives behave normally.
Surprisingly Gentle Song - Xrd's arcade staff roll theme, "Lily", is soft melodic love song amidst a soundtrack of heavy metal thrashing.
Surprisingly Good English - XX's announcer ("Heaven or Hell... Duel 1! LET'S ROCK!"). Accent Core went for a different, equally-fluent announcer, as does Xrd. Overture, being the prime candidate for the title of Oddball in the Series, has its own (female!) announcer and corresponding call ("There's a battle to be won", followed by "Mission Start" in Story Mode or "Round 1. Let's Rock!"/"Round 2. Keep on Rocking!"/"Round 3. Heat it up!"/etc. in Vs. matches); both the Japanese and English system voices use fluent English as well.
That Came Out Wrong - Dizzy didn't really know what she just said to Ky at the end of his first story path in Accent Core Plus (Johnny was the one who told her to say it, for the record). Being a gentleman, he politely pointed out that it wasn't appropriate.
Dizzy: "Then, um...please be gentle...this is my first time..."
Ky Kiske: "U-Um...That's...uh...that's not really appropriate for this situation."
Theme Naming - Some of the characters (and a lot of the attacks) are named after popular metal bands and songs. Additionally, most of the Jellyfish Pirates are named after months of the year.
Third Is 3D - Well, Xrd (with three Xs) uses 3D models as opposed to 2D sprites from the previous games, though technically it's the fourth main fighting game entry in the series (possibly even the fifth if you consider the changes between vanilla XX and Accent Core Plus, both in gameplay and the story department, to be enough for AC+ to stand on its own). In an odd twist, the model animation has no tweening and different shading every frame, making them look much like hand-drawn sprites.
Title Drop - The Guilty Gear is none other than Sol Badguy. Slayer and That Man reveal the meaning to the title, implying Sol is the only Gear capable of sin, because he was the first, and therefore, once human, while all others after him were created for war.
The Tokyo Fireball - Actually extends past Tokyo: the entire nation of Japan has been destroyed prior to the games, and there are no signs that it will be rebuilt. What little survivors remain under government surveillance inside of colonies.
Tokyo Is the Center of the Universe - The survivors of Japan's destruction are now sequestered in a colony as "international treasures." It is implied the government is actually studying them for their affinity for "Ki" magic, the rarest and least understood of the five different magic elements.
Tournament Arc - While the first game took place during a tournament (which, as usual, was Not Just A Tournament), the later games buck the trend and opt for a more complicated story instead.
Unexpected Character - Nobody anticipated one of the new characters for Xrd being a young boy in some kind of bed-mecha hybrid. Named Bedman.
While the home ports of Xrd brought back Sin from GG2 to few's surprise, they also threw another curve with DLC newcomer Elphelt, a cute young thing in a frilly dress with more than a few firearms to her name.
Updated Re-release - The series is particularly notorious for this, almost rivaling the Street Fighter series for how many revisions one of its games has had though some other games have had one or two.
There's been Guilty Gear X Plus, which was Japan-only and featured, amongst other things, the Shadow and Gold versions of everyone, Kliff and Justice as playable characters, a Mission Mode and Story Mode, further fleshing out GGX's rather complex story.
Guilty Gear XX is particularly infamous for this, having 5 (soon to be 6) available versions.
The first was #Reload, which doubled the amount of Missions from 50 to 100, as well as featuring a new, improved and rebalanced version of Robo-Ky with a completely different moveset, as well as some balance tweaks.
The next was Slash, which was Japan-only. This version altered several characters' movesets, several of the stages were largely altered (compare the XX original version of Sol/Ky's stage to the Slash version, where the back wall and door of the stage are now largely wrecked) and most notably, added two new characters: A.B.A from Isuka (which did make it out of Japan) and a new version of Sol called "Order-Sol" (representing during his days as a Holy Knight prior to the first game), both as a playable character AND a secret challenger following I-No.
The fourth version was Accent Core, which managed an overseas release and also featured Order-Sol and A.B.A, marking the overseas debut of the former. This version changed the interface on a larger scale (with a new version of the "Destroyed" pop-up when an Instant Kill was connected), featured a new, less popular announcer and new gameplay options such as Force Breaks, slightly more powerful attacks characters could perform at the cost of some Tension meter, and Slashback, a form of parrying. Several new stages were also introduced and the ones existing already for A.B.A and Order-Sol were altered as well, not to mention the further balancing. The "Generations" modes were also introduced, allowing players to play characters with styles and gameplay similar to GG1 or GGX, though at the cost of other features. However, Kliff and Justice were removed from the roster, and there were no Story or Mission Modes to play through. Furthermore, some Game-Breaking Bugs necessitated the release of...
Accent Core Plus, a console-only version which re-added Story Mode (now set after GGXX's original Story Mode), Mission Mode, Kliff and Justice, as well as fixing some bugs, adding extra Force Breaks, changing some moves and other such things.
Now, there's Accent Core Plus R, which rebalances the characters yet again, including adding Kliff and Justice to the default roster (they had to be unlocked in Accent Core Plus) and making them viable for use in tournaments. This version also saw an arcade release.
Weapons-Grade Vocabulary - Kliff Undersn's taunt creates physical letters, which bounce across the screen and inflict some damage. Knockouts with this in tournament play have become a particularly humiliating form of Cherry Tapping.
Baiken uses something similar but more potent as her Force Break.
Wham Episode - Guilty Gear 2: Overture. It's set after a 5-year Time Skip (with some rather big developments happening during that missing chunk of time), all characters gone except for Sol and Ky (who are redesigned), and all the other settings are gone.