UDONGEIN X (pronounced "Udongein Cross", despite what you'd expect) is a Touhou Project fangame using the gameplay of Mega Man X, released in December 2021.
The storyline is simple. A number of moon rabbits have crash landed in Gensokyo following a failed scouting mission, and it's up to former moon rabbit Reisen Udongein Inaba to rescue them and take them back home. Each of these eight moon rabbits has become trapped in the domain of a certain Touhou boss, and after all eight are rescued, Reisen needs to travel to the Lunar Capital for a final confrontation with her former masters, the Watatsuki Sisters.
The main eight boss characters are:
- Yumemi Okazaki: Fought in the Forest of Magic
- Doremy Sweet: Fought in the Dream World
- Tenshi Hinanawi: Fought at Youkai Mountain
- Fujiwara no Mokou: Fought in the Bamboo Forest of the Lost
- Saki Kurokoma: Fought in the Animal Realm
- Seija Kijin: Fought in the Shining Needle Castle
- Yuugi Hoshiguma: Fought in the Former Hell Capital
- Nue Houjuu: Fought at the Myouren Temple
A paid DLC was released in November 2022. It contains an additional campaign where you play through the game as Seiran, who wields her mochi pounding mallet and focuses more on melee combat like Zero from the Mega Man X series.
See Mega Mari, for a much earlier fusion of Mega Man and Touhou Project.
It can be downloaded for Steam here.
This game provides examples of:
- Achievement Mockery: There are two achievements for dying over 50 times and dying over 200 times.
- Adaptational Wimp: While still an incredibly difficult final boss, Watatsuki no Yorihime can actually be defeated, while she delivered a Curb-Stomp Battle to anyone who tried to fight her in her original story. Then again, she might have let Reisen win.
- And Your Reward Is Clothes: Completing each achievement unlocks an alternate palette for Reisen, such as a Tewi palette for "MERCYFUL FATE" (see Video Game Caring Potential below).
- Anger Born of Worry: After the Superboss fight against Eirin, she admits that the reason she got mad at Reisen for going to the Moon without prior notice was that she was worried about the possibility of Reisen getting herself killed.
- Blackout Basement: The majority of the Extra stage is constantly dark, with only the explosions of defeated enemies lighting up the room temporarily.
- Boss Rush: Averted in the main game, but the optional Survival Mode plays it straight.
- Brutal Bonus Level: After defeating the Final Boss, you unlock an Extra Stage set in Eientei, where you make your way through several rooms dense with enemies and bullets while dealing with Blackout Basement mechanics. The boss is none other than Eirin, who is mad at Reisen for leaving for the Moon without telling anyone back home.
- Bullet Hell: As you'd expect a Touhou fangame to have. Luckily, Hitbox Dissonance is in affect to help you out.
- Damsel in Distress: Eight moon rabbits have been stranded throughout Gensokyo, with many being held captive:
- Tenshi has kidnapped one to keep as a pet.
- Yumemi plans on taking one home for her experiments in magic research.
- Yuugi apparetly is beating up the rabbit who ended up in Old Hell, claiming she's just "giving her an introduction."
- Saki plans on using the rabbit to have leverage over the Lunar Capital, unaware they treat moon rabbits as cannon fodder and thus wouldn't care very much about a hostage.
- While Reisen thinks Seija was holding a rabbit captive, she was simply hiding at the Shining Needle Castle, and Seija didn't even know she was there.
- Easy-Mode Mockery: Achievements cannot be unlocked on Normal mode, only Hard and above.
- Flunky Boss: Tewi Inaba summons earth rabbits during her boss fight, and Nue summons UFOs.
- Gravity Screw: The Shining Needle Castle level has various Yin-Yang orbs that, when shot, invert the gravity for the whole stage. There's an achievement for only doing this four times throughout the entire level.
- Interface Screw: Sagume Kishin uses her powers during her boss fight to temporarily disable Reisen's ability to charge, dash, or wall jump. There are also forcefield gates in the final level that cause the same effect, which can even stack, reverting Reisen's abilities to basically Mega Man 1/2 style gameplay.
- Let's Fight Like Gentlemen: Invoked by Yorihime; when Toyohime throws peaches at her to restore her health, Yorihime gives one to Reisen to keep things fair.
- Mini-Boss: Some Touhou characters appear as midbosses. Among others, Chiyuri is the midboss of Yumemi's stage, Iku is the midboss of Tenshi's stage and Rei'sen from Touhou Bougetsushou is the midboss of the final stage.
- 100% Completion: Beating every achievement unlocks a rainbow color palette for Reisen.
- Red and Black and Evil All Over: All the bosses in Survival Mode gain this coloration and making it to Wave 10 unlocks such a palette for Reisen to use.
- Shout-Out: One achievement is called "DISPOSABLE HEROES".
- Superboss: Eirin Yagokoro, fought at the end of the Extra stage, as she plans on punishing Reisen for rescuing the moon rabbits and going to the Lunar Capital without her orders.
- Turns Red: After her health bar is initially depleted, Mokou suddenly "revives", refilling her healthbar, gaining more powerful attacks, and accidentally burning down the entire Bamboo Forest of the Lost in the process.
- Unexpected Shmup Level: Doremy's stage, The Dream World, and Junko's stage, Kaian Passageway #4, both play more like horizontal versions of Touhou stages. The boss fights at the end are still fought on foot, however.
- The Unfought: Watatsuki no Toyohime simply sits and spectates Reisen's fight with Yorihime, only occasionally tossing out healing items to both sides.
- Victor Gains Loser's Powers: Averted, despite being a Mega Man-styled fangame. Instead, Reisen gains Power items upon defeating the eight main bosses that she can buy various upgrades with.
- Video Game Caring Potential: There's an achievement for not harming any of the Earth rabbits Tewi summons in her intro boss fight.
- What Measure Is a Mook?: There's an achievement called "DISPOSABLE HEROES", for defeating at least 50 moon rabbits during the final level. At the end of said level, Watatsuki no Yorihime even calls out Reisen for beating up so many moon rabbits only to accuse her of mistreating them.
