Legend tells of an artifact that can grant a woman's wish... The Skull Heart. However, if she is impure of heart, her wish will be corrupted and she will be turned into an immensely powerful, twisted being of destruction... The Skullgirl.
A new Skullgirl has risen; who will defeat her and claim the Skull Heart?
Developed by Reverge Labs, published by Autumn Games and Konami, and currently maintained by Lab Zero Games, the frenetic 2D Fighting GameSkullgirls puts players in control of an all-female cast a laArcana Heart. The game combines Animesque character designs with a stylized "Golden Age" Hollywood film motif, employing Art Deco (referred to as "Dark Deco" by the designers in honor of Batman: The Animated Series which coined the term and art style.) stage backgrounds and a cinematic presentation. Skullgirls features work from an all-star development crew: fighting game veteran Mike "Mike Z" Zaimont (he of REAL SOVIET DAMAGE fame) led the project, Cristina Valenzuela directed the voice acting, Alex Ahad (whose prior work credits include Lava Punch, Studio UDON’s Tribute books, and promotional art for Scott Pilgrim) created artwork for the game, and Michiru Yamane provided the music. The result is an eclectic and delightfully quirky cast and setting.In the Canopy Kingdom, female combatants fight in an attempt to control the enigmatic Skull Heart, a mysterious MacGuffin with the power to bestow wishes — but not without a substantial price. Should the victor possess an impure soul, the Skull Heart corrupt both her wish and her physical body into a living nightmare that haunts humanity: a monstrous entity known only as the Skullgirl. In the middle of a war with two other nations, the Canopy Kingdom's queen won the Skull Heart and wished for peace. In a way, she got her wish: after transforming into the most powerful and dangerous Skullgirl in history, all three countries agreed to stop fighting each other in order to save themselves from the Skullgirl. When the game's story begins, the now-ended war remains fresh in everyone's minds, and rumors say a new Skullgirl has risen Skullgirls' gameplay carries the feel of old-school arcade fighters while providing a high-definition twist. It features a "ratio system" that allows each player to choose to fight with one character or a team of up to three characters, resulting in different combinations for a particular match. The game also features a special combo detection system: if a player begins an infinite combo, the damage strikes change color, and the game will allow the opponent to "burst" out of the infinite and knock the offensive player away.The cast of characters includes Filia, Cerebella, Peacock, Parasoul, Ms. Fortune, Painwheel, Valentine, and Double. Check the Character sheet for more information on all of them. One DLC character, Squigly, was included with the beta and final release of the PC version, with the release for the console versions coming soon, having been funded thanks to a crowdfunding drive. Another, Big Band, is planned to be the first male DLC character. The third and fourth (fan-voted characters from the crowdfunding drive) are Eliza and Beowulf. The team at Lab Zero has also confirmed 25-28 possible future DLC characters (all of which could be Saved for the Sequel).Both the PlayStation Network and Xbox LIVE Arcade carry the game in the US, Europe, and Australia, and the game's available to PC gamers through Steam. A version of the game with translated text was published by Cyber Front on the Japanese PSN in February 2013; despite Japan's general mild distaste for downloadable games, Skullgirls became a smash hit. (There are currently no plans for a Japanese XBLA version.) Due to legal issues surrounding the developers' rocky relationship with Konami (see below), the original PSN and XBLA releases of Skullgirls will be delisted at the end of 2013; Lab Zero will republish the game on both services in Febuary 2014 as Skullgirls Encore at least for PSN (due to specific platform differences, PSN's version of Encore comes as an entirely new standalone release, while XBLA's version patches the original Skullgirls release).The game was notably in an aftermarket Development Hell, due to a serious case of Troubled Production. Most of the post-release content, including the first patch and the first DLC character, was delayed because the Skullgirls team members were laid off from Reverge Labs (the original studio). This was due to Konami's and Autumn Games's (the publisher and owner of the Skullgirls IP) being hit with an unrelated lawsuitnote According to official sources, it involvesDefJam Rapstar which tied up financial assets intended for the developers. Thankfully, Autumn Games helped them back up by supporting their new independent company, Lab Zero Games, as reflected on the newly-patched intro screen of the game. Lab Zero then started a fan fundraising project to get new content out, which became much more successful than anyone expected it to be. Originally set to fund just one characternote who was one-third done before the Troubled Production and the fundraiser began, the fundraiser raised enough to fully fund a total of five DLC characters, each of them with their own DLC stage and story mode! (And two more stages were added thanks to Contest Winner Cameos.)
Make it flashy guys...ACTION! Skullgirls proudly presents the following tropes:
Aerith and Bob: Well, we've got characters with names like Filia, Parasoul, Cerebella, and Umbrella, alongside others with names like Adam, Patricia, Carol, and Nadia. Sort of downplayed, though, since there are a lot more Bobs than Aeriths.
Affectionate Parody: If, by some miracle, you defeat Marie 300% in Squigly's joke "story mode" (which consists of just that boss fight), you get a parody of anime episode previews narrated by Filia and Samson, complete with Japanese title cards and excessively lengthy episode name.
Animesque: Made by Americans, but Japanese enough in feel to get backing by Konami.
In Squigly's tentative story mode included in the games extra menu, Marie asks when her real story mode is going to come out. Squigly's response? "Two weeks!" Marie is not pleased.
Marie 300%: I'll teach you to troll me!
As Long as There Is Evil: The Skull Heart can never truly be destroyed; it always return every seven years to turn those with dark desires into Skullgirls. (That is, unless The Trinity has any indication).
Aside Glance: One of the things Peacock can drop on her opponent is a fully grown live elephant, which not only survives the fall unharmed, but gives one of these glances at the player.
Ballroom Blitz: The fourth DLC stage, Glass Canopy, is a massive ballroom first seen in a background in Parasoul's story mode.
Beating A Dead Player: You can continue your combo on a defeated character to gain meter. As of the upcoming patch, this has been changed so that the living player will no longer gain meter, but the opponent still does.
Beat Still, My Heart: The Skull Heart is both a skull and a heart, with glowing blue blood vessels that spread out and provide the platform for the final stage.
Be Careful What You Wish For: The Skull Heart can grant any wish, but if one's heart is even the slightest bit impure, or the wish even slightly selfish, they will turn into a Skullgirl, and their wish will be perverted. The queen of the Canopy Kingdom wanted to end a global war. She got her wish, but only after becoming so dangerous a Skullgirl that the warring nations set aside their differences to stop her.
Bloodless Carnage: The characters are stabbed, shot, crushed, blown up, and God only knows what else in-game, yet there's far less actual bloodshed involved than you would expect. There are a few exceptions... but see the character sheet for more details.
Breaking the Fourth Wall: When Peacock's getting ready in the morning, Andy asks Avery if she even took a bath and if she brushes her teeth with metal polish. Avery's response is that a bath and her usual morning routine were implied, but not something the audience needs to see.
Cat Fight: Since the majority of the roster are women, expect this to happen a lot.
There's even a cat woman who often meows when attacking or being hit and a lot of her attacks are scratches.
Cliffhanger: Double's Story Mode path ends with two girls playing the game and mentioning the existence of "other routes." According to the devs, it's essentially a fancy and long-winded way of saying that none of the various plotlines are Canon, but that there will be a single unifying storyline sometime in the future.
Combo Breaker: Tied in to the game's "Infinite Prevention System." You can only burst out of a combo when the IPS detects an infinite.
A new mechanic in Squigly's patch update introduced a different kind of combo breaker, where instead of bursting out of a combo when the sparks turn red, you can just hop out of a combo when the sparks turn green. This is referred to as "undizzying", based on the mechanic in Marvel vs. Capcom 2: New Age Of Heroes; this was introduced as an alternate escape method after clued-in players began deliberately using infinites to bait their opponents into bursting in order to take advantage of the (extremely) short cooldown period.
Conservation of Ninjutsu: Used as a game mechanic. The more characters you have on your side, the weaker each individual character is.
Contest Winner Cameo: This is one of the rewards in the Indiegogo crowdfunding campaign. It became popular enough to result in the announcement of two new stages, simply to show everyone's characters. (Keep in mind that each of these people had to donate $1,500 or more to get their characters into the game.)
Matt and Woolie, Zone-tan (ZONE's mascot), and Sanshee's mascot all will appear as background characters in the River King Casino.
Corrupt Church: One of the story mode's paths suggests that the Trinity may be the source of the Mineral MacGuffin's power. Even the cathedral architecture and sculptures suggest one of the characters as quite representative of the church's true nature.
Cosmic Horror Story: Double's ending reveals the characters and fate of the story are being controlled by Aeon and Venus's arcade stick, and suggests that none of the storylines are Canon.
Creator Cameo: One of the bullies hanging out in Maplecrest — the guy with the black star on the back of his jacket — is designed to look like one of the game's animators. Several of the developers' dogs can be seen in the same stage.
The Infinite Prevention System - The game knows when you're trying to pull off a proper infinite combo (a.k.a. a loop) and allows the player being hit to burst out of it. At the same time, the system is lenient enough that players can rack up huge extended combos as long as they don't start repeating themselves.
Unblockable prevention - The game knows when you've been put in a true unblockable situation, where blocking one attack means getting hit by another, and requires you to only block one (whichever hits first, or either one if they would hit at the same time). At the same time, the game allows for "hard-to-blockables" — where it seems that you're faced with a true unblockable situation, but you can actually block both attacks if you time it right.
The game requires you to hold Start to pause the game. This is necessary to prevent the players accidentally pausing the game in the middle of a tournament match, which is frequently grounds for disqualification, though it's just as appreciated by Button Mashers.
360 detection - The game recognizes when you are inputting a 360 motion, which usually ends with an up direction. This can end with the character jumping and attacking instead of performing a special throw (as the motion usually requires) if you're not fast enough. So instead, the game keeps you on the ground as seen here, to make intended 360s easier to perform.
The game prides itself on the high count of animation frames. When you switch in a character and not all of its animation loads in time, your character's hitboxes show instead as an error handler, just so that there's something there. It doesn't last for more than a split-second and it's fairly rare.
As of the first major patch, this is replaced with the characters appearing as de-rezzed versions of their usual art. "Looking all 8-bit", in the words of the creator.
The game actually uses a shading layer and depth map for its sprites. Not only does this speed up the art process, it also allows for some amazing lighting not usually seen in 2D games.
How about turning on hitboxes during Practice? How many other fighting games do that?
The patch adds savestates to the training mode, for repeatably testing out different scenarios. Savestates are cleared by holding down select. They can also be cleared by pressing LP+LK+select, because somebody alerted the developers that some types of dual-moddednote Modified by hardware hackers to be compatible with both 360 and PS3 consolesfightsticks can't register "holding down select."
There's a small icon that indicates who is leading in total health.
The patch also introduces a mechanic based on Marvel vs. Capcom 2: New Age Of Heroes where hitting both the point character and assist character with a snapback attack leaves the assist character open for combos. Because it's impossible for the IPS to trigger on an assist character, the assist is trapped in a potential infinite loop resulting in a KO. As compensation, whenever a double-snapback occurs, the game detects it and automatically regenerates the meter of the player being comboed, so as to prevent the attacker from having too much of an advantage.
Diesel Punk: The game's setting is a weird amalgam of thirties-forties United States and Europe, with incredibly advanced technology housed in Art Deco architecture.
Dominatrix: Concept art shows someone named D. Violet.◊ Strangely, Filia's teacher Ms. Victoria has concept art that identifies her as D.Violet.
Confirmed to be one and the same, and Miss Victoria may not even be aware of it.
To make things weirder, they seem to be planned as separate characters.
Double Meaning: Peacock usually says "Poke!" during her Low Punch move, not just referring to how she's literally poking the enemy, but to how using Low Punches or Low Kicks to keep an opponent at bay is called "Poking".
Filia: Deciding that her regaining her memories wasn't as important as ensuring Carol (Painwheel) had a chance at happiness, Filia wishes for Carol to have a normal childhood. The Skull Heart grants the wish, but because the wish was to a small extent self-serving, it was impure. As a result, she would become the next Skullgirl. The transformation would be slow, though, and the Skull Heart advises Filia to use her remaining time well.
Peacock: The Skullgirl, Bloody Marie, turns out to be a childhood friend of Peacock. Peacock kills Marie to free her from the Skull Heart's control, then destroys the Skull Heart. Afterwards, she vows to continue Marie's work: destroying the Medici family, the ones who injured Peacock and forced Marie to find the Skull Heart...
Parasoul: To save her younger sister Umbrella from becoming the next Skullgirl (and because shooting the Skull Heart would set off an explosion that would kill Umbrella), Parasoul wishes for Umbrella to not become the Skullgirl. The wish is granted, but Parasoul would eventually become the Skullgirl in Umbrella's place. Like Filia, though, her transformation would be slow, so she begins Umbrella's combat training shortly thereafter, knowing that once she transforms, Umbrella would have to kill her...
Painwheel: After destroying the Skull Heart, Painwheel returns to her home in Maplecrest. Her parents reject her, however, because of her grotesque appearance. With nowhere else to go, she returns to Lab Zero and begins to plot her revenge against Brain Drain and the Anti-Skullgirl Labs. With the implication that she is somehow going to be the next Skullgirl...
Cerebella: Word of God is that she's the only one with a pure enough heart to make a wish without turning into a Skullgirl. Her affection for Vitale, however, means that she never gets the chance; instead she's forced to murder Ms. Fortune both to protect him and to recover the MacGuffin he sent her to retrieve, leaving her broken and confused.
Valentine: We discover that she was in fact a Reverse Mole and possibly a Stealth Mentor to Painwheel, to whom she seems to harbor remorse for turning her into what she is. She kills Marie, and at first considers using the Skull Heart to resurrect the other members of Last Hope, but knows the Heart is a Jerkass Genie and will likely corrupt that wish. So she instead wishes flat out to become the next Skullgirl, with the implication that she wants Painwheel to hunt her down and kill her to atone for what she had done to her.
Squigly: Double reveals she was behind the events that exterminated Squigly's family. With Filia's help, Squigly defeats Double and destroys the Skull Heart. Unfortunately, Squigly's exsistence is still tied to the Heart and she passes away again. Her only comfort is that Leviathan swears to stay with her until her next awakening. At the end of the credits, we see Filia visiting Squigly's new grave.
Downloadable Content: Squigly was fully funded in a day and was released August 2013. Big Band will be the first male character added, with Eliza, Beowulf, and Robo-Fortune following. See also Gag Dub below.
The series has another brush with Persona due to Beowulf, a wrestler who fights with a folding chair. The character was around some time before Ms. Fortune's design changed, but most of us heard of Persona 4 Arena first.
Amusingly, in the list of characters and games that inspired Beowulf, one of the items is "NotKanji"
Fanservice: It's a fighting game with an all-female cast. This shouldn't be a surprise.
Fan Disservice: While there's an underlying theme of playful fanservice running through a lot of the characters, there's an equal amount who totally turn it on its head. Sure there's busty gals in Form Fitting Wardrobes like Valentine and Cerebella, but then there's:
Painwheel, a Broken Bird in a revealing Qipao, who was experimented on and brainwashed into being a berserk warrior that attacks with her extended spinal cord and spikes that pop out of her skin, usually while roaring in agony.
Funny Background Event: In the Class Notes stage, Ms. Victoria will react in surprise toward particularly powerful attacks (such as Cerebella's Diamond Dynamo blockbuster or Peacock's fully charged Shadow of Impending Doom special).
Gag Dub: The voice actors have recorded videos of themselves playing the game and doing gag dubs for their own characters. For a charity donation drive they even did this for playthroughs of the story mode (see the Funny Moments page for more details). This culminated in Gag Dub voice packs being announced and funded for the Indiegogo campaign, they are, as follows:
Similarly, there's the fact that Filia is underage, despite her still being played for fanservice.
The amount of Gorn is incredibly high for a T-rated game. Ms. Fortune dashes by jettisoning her own blood around and uses her muscle fibers in various attacks. Valentine's level 3 Blockbuster shows off copious amounts of blood. There's also Eliza's gimmick, using her own blood to attack the opponent. An M-rating was likely only avoided because of the fact the game doesn't use 3D models.
Some of the voice lines when characters are defeated, as well as Valentine's use of a Magical Defibrillator to revive a teammate, suggest they may actually die when KO'd. This even includes a line from Peacock.
Guide Dang It: When the initial release hit, there were no in-game move lists. Players had to go to the game's website to obtain the characters' move lists in PDF format. Now, moveset lists can be accessed in the pause menu, complete with a feature that shows only the movesets of the characters(s) the player is currently using.
The achievement titles & descriptions are rarely helpful. One references medicine & surgery but requires you to use a defibrilator in a certain way. Another tells you to throw stuff but actually only requires you to drop stuff. The one that says to let the weight off your shoulders requires you to play as Ms. Fortune & leave your head off for an hour in total. Most of the achievements have tons of ways they could be interpreted & the requirement usually has to be met a large unspecified amount of times but you have no way to know whether or not you're meeting the requirement.
And then some are just intentionally bizarre, the most cited example being 32 hits — "Anatiferous"note Literally "producing ducks", after the belief that geese and ducks spontaneously generated from barnacles.
Ladies and Germs: As the announcer says "Ladies and Gentlemen," a question mark briefly flashes next to Gentlemen as a reference to the absence of male characters to choose from.
A Lighter Shade of Grey: Anti-Skullgirl Lab 8 is this to Lab Zero. Both produce super-powered child soldiers to fight the threat of the Skullgirl. But whereas Lab 8 takes in war victims and, with their blessing, gives them upgrades, Lab Zero's only known subject, Painwheel, was an innocent girl kidnapped off the streets and brainwashed into a fighting monstrosity.
Literal-Minded: A snapback is a specific type of move in tag fighters such as this game. When used, they force the opponent to tag out. In Skullgirls, they're called "Outtakes" - as in, literally taking the opponent out of the fight.
Living Weapon: Erm...Living Weapons. Word of God has stated that unlike Parasites, Living Weapons are not sapient; they are conscious when in use, but strictly subsentient, more or less in the manner of intelligent animals. They also don't bond with the user the way Parasites do.
The Mafia: The entire Cirque de Cartes works for them, whether they want to or not.
Meaningful Funeral: Squigly's funeral, paid for by Lorenzo. Subverted though, since the Continello family were murdered on his orders. In the end of her storyline, Squigly is re-interred by Filia, away from the city.
The whole point of Cerebella's story arc is Moral Dissonance: she's a fundamentally pure and good-hearted person who owes her entire life to a fundamentally rotten and outright evilgroup of people. Her ending suggests that she's been high-minded enough to accept the contradictions in her life until circumstances force her to commit her first murder, to keep Ms. Fortune away from Vitale.
Also, the Skull Heart mentions that it's Filia's wish that isn't completely pure, because of her forgotten guilt of being cruel to Carol/Painwheel in the past.
Multiple Endings: There is a canonical true ending, as yet unrevealed, but the endings in the game's initial Story Mode are all "Threads of Fate" for each individual character's triumph over all the others, in which will all have a single common point where they converge.
Nice Hat: Extra points to Cerebella's, which is alive.
Nighthawks Shot: The first scene of Filia's story mode takes place at a cafe that strongly resembles Nighthawks.
No Fair Cheating: The PC version is coded to instantly kill anyone who plays as Marie or a character they do not own online, and playing as Marie online is planned to zero out a players win count and TrueSkill.note TrueSkill is a value used to match people of equal skill in online matches. Even the worst of players cannot get zero TrueSkill, so Marie players would only be able to play against other Marie players.
No Swastikas: The Black Egrets flag is based off of Nazi Germany, but with an umbrella.
Obvious Beta: The pre-patch version of the game. The Xbox 360 version suffered from this longest due to Microsoft's very strict file size patching limits, but it was eventually patched months after the PlayStation 3 version.
Obvious Rule Patch: While the Infinite Prevention System is useful, people were still able to find ways to pull off insanely damaging, even lethal, combos without triggering it. This lead to the addition of Stun, which puts a hard limit on how long a combo can be when the player can't get out of it.
On the Next: Parodied in Squigly's Joke Story Mode ending.
One-Woman Wail: The main theme music — a remix of Marie's stage theme, which also fits the trope.
Only One Name: Zig-Zagged. The full names of a little over half the playable cast - Parasoul (Renoir), Squigly (Contiello), Big Band (Ben Birdland), Peacock (Patricia Watson), and Ms. (Nadia) Fortune - as well as the Medicis, Squigly's family, Parasoul's family, Marie (Korbel, according to Word of God), Adam (Kapowski, also as of Word of God) and Stanley (Whitefin), have been revealed. Every other character, including every DLC candidate besides Stanley, Marie, and Adam, have no revealed full name. Dr. Avian is unique in that we only know his last name.
Filia at least has the excuse of simply forgetting her last name. (It's almost certainly Medici, though.)
Our Giants Are Bigger: Gigans have their own nation with a violent history with the Canopy Kingdom, a reputation as berserkers hungry for battle, and are interfertile with other races. Scythana is part-Gigan, but no full Gigans have appeared as yet.
Panty Fighter: Might be some Author Appeal in it all, given how frequent and almost intentional it seems (the end of Cerebella's grapple super has her do a handstand, revealing her thighs and then some). The game isn't overtly sexual but no doubt that it tries to be cheeky.
Power Creep, Power Seep: The characters' strength is adjusted depending on whether or not they're fighting in a team or alone.
Product Placement: Billboards for various real-world sponsers of the game, such as EightySixed and Sanshee, can be seen in the background of some stages. In addition, the developer build of the game is streamed on the EightySixed Twitch.tv channel.
Punny Name: Almost the entirety of the playable cast. Many other examples as well - check the characters page for the full list.
Cerebella is a pun on "cerebellum", a region of the brain. Cerebella's primary weapon when fighting is a hat.
Painwheel's most distinguishing feature is the giant metal pinwheel sticking out of her back.
Ms. Fortune's name is a pun on the word "misfortune", which makes a bit of sense considering she's kind of a zombie.
Bloody Marie's name is a pun on "Bloody Mary".
Valentine's name is a pun on her real name, Valerie. It also ties into the Last Hope's Theme Naming after holidays.
A non-character example in two stages: Under the Bridge literally takes place under a bridge, and Glass Canopy is a massive ballroom with a a glass canopy for a roof. The name of the country the game takes place in is the Canopy Kingdom.
Recurring Riff: Those first nine notes you hear in the opening? They play a lot throughout the course of the game, mostly in the cutscene music for the story modes.
Red Eyes, Take Warning: Quite a lot of characters have them. They either have parasites implanted in their body, or have a connection with the Skullgirl.
Secret A.I. Moves: Sometimes, computer assist Peacock will use her charged up Shadow of Impending Doom (item drop move). You cannot have your own Peacock assist do this. You also can't do Painwheel's charged up attacks as assists, something the computer player also periodically uses.
Patches have since added the ability to set charged Shadow of Impending Doom as an assist, but good luck finding out how.* QCB LP+MP for light, QCB MP+HP for medium, QCB LP+HP for heavy.
Sequel Hook: Double's (the final story mode's) ending. Technically, it's a True Story Mode hook.
Show Within a Show: There's a show called Annie: Girl of the Stars. Peacock and Parasoul (secretly) are known fans of it, but ironically not Umbrella.
SNK Boss: Bloody Marie. She was notorious for being exceedingly aggravating to beat with most characters (save for Peacock, fittingly enough) before the game was patched. Even after the patch, which added hitstun and more visibility on her attacks, she remains a difficult boss.
Some Dexterity Required: Averted, which is a a big deal for a tourney-level traditional fighter. The most complex joystick motion is a single full circle forward, and the only character that uses it is Cerebella, and even then, only for a super.note The game also has a 360-detection system that prevents you from accidentally jumping when trying to do this. Stringing lengthy combos together takes a bit of practice, but pulling off the moves individually is no sweat.
In Valentine's Story Mode she steps in between Painwheel and Double's fight, prompting Double to call her a "double-crosser." She's referring to Valentine's ambiguous alliance of course, but given that she's literally crossing Double... And Valentine's red crosses...
When Valentine tags out with Double, one of her lines is "Prepare for trouble!" "And makeit Double!".
Super Move Portrait Attack: A patch gave Blockbuster attacks character portrait cut-ins at the same time as the super flash. They also cause the screen to go sepia-tone for that split-second.
Super Soldier: The projects from the Anti-Skullgirls Labs. Peacock and Painwheel are two of them. Concept art of Panzerfaust shows him to be a very literal interpretation, being a hulk of a uniformed soldier with a tank for a hand.
Standard Parasites attach themselves to the user's body and display sapient-level intelligence and speech. Word of God says that after the Parasite is attached, the Parasite and its user will die if separated (though it's possible to transfer a Parasite from one user to another without killing the Parasite).
Finally, Synthetic Parasites are artificially created and implanted into the user's body. However, they do not display speech or intelligence and in fact may not be truly alive.
Symbol Motif Clothing: Skull shapes. They're visible on the outfits of quite a few characters, such as Marie's hairpins and Squigly's corset. If you look close, Filia has skull-shaped cufflinks.
There's also Cerebella's thing with diamonds; all the members of the Cirque des Cartes have card-related motifs.
Tag Team: If there's a two- or three-(wo)man team involved.
Take That: The list of changes on the v1.01 patch includes the note "Prettied up that billboard on the Medici Tower stage." By "prettied up", they mean "ditched the Reverge logo and replaced it with the Lab Zero logo".
Theme Naming: All the members of Last Hope are named after a different holiday.
Valentine: Valentine's Day
Patty: St. Patrick's Day
Title Confusion: People seem to think that the title refers to the seemingly all-girl cast, but it refers to the game's central plot and antagonist. The demo, where the only two playable characters are Filia and Cerebella, seems to give people the idea that all the girls fight with their head/headgear. And to add to the confusion even further there's only one actual full-blown Skullgirl in the game (and she's not even playable); the rest only appear in flashbacks or implied transformations in the endings.
Also Patty from The Last Hope if you include non-playable characters.
Womb Level: Final Atrium, the area where the final boss is fought, is made of demonic blood vessels that glow blue. Why is this? Because they're a part of the Skull Heart.
World of Action Girls: Naturally, given the all-female cast, but even non-playable women have a disproportionate tendency to be badass.
You Fight Like a Cow: Using a tech will often prompt the opponents to briefly exchange insults with each other, usually with the one who recovered expressing pain and the attacker mocking them. For example: