Kamen Rider Climax Heroes

A series of 3D fighting games developed by Eighting Raizing based on Heisei era of the Kamen Rider franchise, where characters from Kuuga to, currently, Fourze duke it out in one-on-one fights.

The series currently features four games in Japan, which are actually more like updates of the previous one than sequels:
 * Kamen Rider: Climax Heroes (Playstation2), includes main Riders from Kuuga to Decade as well as a few hidden secondary riders that don't necessarily have complete movesets. Many Riders have the ability to change into various forms...but only for a limited amount of time.
 * Kamen Rider: Climax Heroes W (Wii), pretty much the same deal but with Double added to the cast. A number of systematic changes were also implemented such as usage of "incomplete" characters outside of story mode. It's more of Updated Rerelease, with Double being only one with complete movesets from the handful of new characters.
 * Kamen Rider: Climax Heroes OOO (Wii and PSP), guess who got added in this update. The main Riders' final forms are finally fully playable instead of being seen only for Finishing Moves. Surprisingly, the "hidden" secondary Riders are not hidden under the main, finished characters; unlike the first two games. Also every Rider from Ryuki is there, copypasted from the Kamen Rider Dragon Knight game (see below). The Ryuki Riders have an important role in this game's story mode, known as Ragnarok Mode, based on the Mirror World from the Kamen Rider Dragon Knight game.
 * Kamen Rider: Climax Heroes Fourze (Wii and PSP again). Guess who got added in this update. Showa Riders also got added, OOO got all his forms except for TaMaShii, you can now do tag battles where you can change between two Riders mid-fight or use your Super Gauge to summon your other character to sandwich the opponent, and all the Obvious Beta characters finally got a Finishing Move as well as a pseudo Super Mode where their power increases and a few of their combos change.

There has also been one Climax Heroes game released in the U.S., though not released under that title: Kamen Rider Dragon Knight for the Wii, developed by the same company and based on the same engine, but with the characters modded into the cast of Kamen Rider Dragon Knight, some altered mechanics, and an original story mode called Mirror World.

Tropes presented by Kamen Rider: Climax Heroes:

 * A.I. Is a Crapshoot: Ragnarok (Originally "R-1000") in Climax Heroes OOO was designed as a Deus Est Machina, but went haywire.
 * Beat'Em Up: Most missions in OOO's Ragnarok Mode play out like this (Something carried over from Dragon Knight Wii).
 * Calling Your Attacks: Not everyone does this, but there are a few instances. Mostly for characters from Kamen Rider Kabuto, where this trope was commonplace. Double and Den-O Liner Form also do this for their Finishing Moves.
 * Blade and Garren, on the other hand, have their attacks called for them by their weapons.
 * With the adding of Showa characters and Fourze to the cast, we can expect even more attack calling.
 * Counter Attack: Kabuto's normal Rider Kick functions as one. In addition, Decade gains one if he has Final Form Ride: Kabuto Zecter selected as his summon in Form Change style.
 * Dolled-Up Installment: The Kamen Rider Dragon Knight game for the Nintendo Wii is Climax Heroes W with the serial numbers filed off and all of the Riders' standard movesets copied and pasted onto the characters from that series. For the curious, they are:
 * Dragon Knight and Onyx/Ryuga = Ryuki (Duh)
 * Wing Knight/Knight and Siren/Femme = IXA Burst Mode
 * Activating Knight's Sword Vent makes him play like Zeronos, activating Femme's turns her into Dragon Form Kuuga
 * Incisor/Scissors, Axe/Tiger and Wrath/Odin = Agito
 * Torque/Zolda = Diend
 * Divergent Character Evolution: Diend was given a brand new moveset in OOO, so it's very difficult to tell that he and Zolda were ever the same character.
 * Sting/Raia and Camo/Verde = Mighty Form Kuuga
 * Thrust/Gai = Decade
 * Strike/Ouja = Faiz
 * Spear/Imperer = Kiva
 * Wing Knight Survive/Knight Survive = Blade
 * Early Installment Weirdness: In the first two games, Ryuki and Diend use new finishing moves. They regain the ones they used in their respective series in Climax Heroes OOO.
 * Evil Twin: Dark Decade, the Final Boss in first two games. He's an alternate version of Decade, much like alternate riders in the series. He fights just like Decade, except being far stronger and doesn't has Final Form Ride cards.
 * Face Heel Turn: A number of Riders in Ragnarok Mode have been brainwashed by the eponymous computer into fighting for its amusement. Naturally, you'll have to "befriend" them.
 * Final Boss: Dark Decade, a Palette Swap of Decade with increased offense and defense, served this purpose in the original Climax Heroes and W. OOO cut the character entirely and replaced him with Odin and Ryuga. In Fourze, the Heroes Mode doesn't seem to have a specific story since you can do missions with any Rider in any order. Odin is still there, but the Twin Hoppers tend to appear very often as the final match in arcade mode, and when it's not them, it's Fourze and OOO, unless you've fufilled certain conditions, then its Purple Eyed TaToBa OOO.
 * Flunky Boss: Occasionally, a mission in Ragnarok Mode will require the player to defeat an enemy Rider in a Beat'Em Up stage, where they will fight alongside Mooks. Notable among these is Diend, who always fights alongside Riotroopers (This particular Mook is never encountered unless you're up against Diend).
 * Heel Face Turn: Several antagonistic Riders such as Kaixa, the Hoppers, and most of Kamen Rider Ryuki's cast will join up with the player in Ragnarok Mode. Of course, you'll usually have to beat them first.
 * Of course, Imperer pulls a Face Heel Turn later on, and Kaixa walks into a Heel Face Revolving Door, though unlike Imperer he ends up on the player's side.
 * Joke Character: AutoVajin, Faiz's Transforming Mecha/Coolbike. He's slow, doesn't have a finisher, and has almost no combos. Probably an in-joke as he was quite useless and stupid in the series itself.
 * Lethal Joke Character: In the first two games, however, he's a Stone Wall, as he hits hard and doesn't get stunned by weak attacks.
 * Limit Break: Based on each Riders' Finishing Move in respective titles. Here are all that are included in Fourze.
 * Mooks: In the form of of Gelnewts, Raydragoons, Salisworms and Masquerade Dopants in OOO's Ragnarok Mode. Shocker mooks also appear in Fourze.
 * Obvious Beta: Some of the secret characters don't have a Super Mode or even a finisher. Nega Den-O doesn't have the abilities we would expect from him, Gatack and the twin Hoppers only have their signature finishing moves as special moves but no cinematic finisher, AutoVajin is a complete joke with almost no moves (maybe it's a case of Joke Character) and.
 * Corrected in Fourze, all the incomplete characters got new/improved moves, a finishing move and can use their Super Gauge to enter a temporary Super Mode with increased power and a few different combos.
 * The Other Darrin: Most of the Riders don't have their original actors voicing them, the ones that do are usually the more recent ones, as well as some whose original actors are not constantly overbooked by other productions because of their popularity.
 * Super Mode: Different versions, depending on what gauge colour is chosen, in Climax Heroes OOO and Fourze (in the original and Double, all Riders act as Red Gauge Riders, sans for the Kamen Rider Kabuto Riders and Faiz, and those who act as gray gauge characters):
 * Multiform Balance: Green gauge characters, who can change between different forms at will (Kuuga, Den-O, Decade, Double and OOO can all use this gauge in Climax Heroes OOO, as can Fourze as of his installment)
 * Super Mode: Red gauge characters, who can change into a more powerful form when their Rider Gauge is full, and use this to cancel their actions (All main Riders except for OOO + Zeronos and Accel can use this gauge in Climax Heroes OOO. In Climax Heroes Fourze, OOO and Black RX can use this gauge, as well)
 * Super Speed: Blue gauge characters, who can enter a state in which everything but them is slowed down for a limited time when their Rider Gauge is full (All Kamen Rider Kabuto Riders, as well as Faiz, can use this gauge)
 * Summon Magic: Orange gauge characters, who can summon allies to help them for a fraction of their Rider Gauge (Kuuga, Agito, all Kamen Rider Ryuki Riders, Faiz and Kiva can use this gauge, as well as V3 as of Climax Heroes Fourze)
 * Riders with a gray gauge get no Super Mode whatsoever (Everyone not mentioned in the previous list and Double can use this gauge, and many more in Fourze). In Fourze, characters with a Grey gauge can now power up and get a few new moves for a limited time.
 * Two characters have "special" versions of the gauges: Kamen Rider Kabuto Hyper Mode is a Red Gauge, yet can activate Clock Up as if he was a Blue Gauge. Kamen Rider Decade's Kamen Ride is a green gauge, yet it can cancel his actions as if it were a red gauge.
 * Swiss Army Hero: A few main Riders have this as their gimmick when you choose to use them in form change mode.
 * Kuuga: Mighty Form, Dragon Form, Pegasus Form, Titan Form.
 * Agito is supposed to do this, but only has access to Trinity and Shining Form, both as Super Mode, and you can only choose one for the entire fight/story mode level/arcade playthrough.
 * Den-O: Sword Form, Rod Form, Axe Form, Gun Form.
 * Kiva, like Agito, is reduced to only having Emperor Form, with his other forms nowhere in sight.
 * Decade does his Mega Manning like in the series, but can only choose one of the first nine Heisei Riders for all the fight/level/arcade mode.
 * Double can mix and match his Gaia Memories like in the show.
 * OOO works like Double, with 4 head medals, 3 arm medals and 3 leg medals that you can mix the way you want. But using strong attacks tends to choose either your arm or leg medals and turn the other parts of his body in the same type to make a full combo. Using weak attacks or specials will not force-change you, but it's kinda awkward to be reduced to that in order to stay in mix-and-match combos.
 * Fourze can either use his 4 basic switches plus 4 other you choose before battle, or use his 4 basic switches and change into Elek States or Fire States.
 * Theme Song Power Up: A gameplay element in OOO. Each series has a theme song that will play whenever a Rider from said series executes his Finishing Move or enters into "Climax Time" (Occurs if the Rider can wear his opponent down to 1/3 health first and gives the winning Rider a full super gauge). The best part? You can choose your own theme songs in the PSP version thanks to the Custom Soundtrack option.
 * The Unexpected: The final character to be unlocked in Climax Heroes OOO is Kamen Rider Double... CycloneAccelXtreme. A form that up to this point only officially existed as a five second Imagine Spot.
 * In Climax Heroes Fourze, Showa Riders got added! Up until then, the series was only about Heisei Riders.
 * Similar to the CycloneAccelXtreme example, yet to a lesser extent, OOO's Purple Eyed TaToBa Combo can be unlocked in Fourze. Much like CAX, this only appeared for about five seconds.
 * This is at the cost of CAX. On the plus-side, and even more unexpected, Purple Eyed TaToBa HAS got a finisher, unlike CAX... the downside is that it's the regular TaToBa finisher with Purple Eyes and different sounds (growls and grunts, which is at least consistent for PE-TaToBa).
 * What If: Although it's just text, some of Hero Mode storyline in Fourze is this. For examples - Scissor survive his canon death, but become fugitive as his crime got uncovered, and Shadow Moon retains Nobuhiko's personality.