The evil wizard Namakura, president of the Aomekakushi Party, seeks scrolls of power to make himself into a super awesome ninja. Namakura orders the the ninja named NIN-JA to collect them all. However, NIN-JA is busy staring at his love, Princess Sakura. Consequently, Namakura kidnaps Sakura and tells NIN-JA that if he collects all the scrolls then Sakura will be released. NIN-JA accepts.
The game's art style simulates an old theater with painted backgrounds and paper puppets held on sticks. The audience is a bunch of children who have to watch it for school or something like that, and who frequently make comments on what is happening. Even while the game is paused or is at the main menu, the children are still there, getting bored out of their skulls and complaining out loud because the game is not happening. They need ninja action to sate their ninja appetites.
The game itself is divided into five ninja worlds with ten ninja stages each, and also has a Score Attack mode for each of the five ninja worlds, influenced by the pacing and structure of Mushihime Sama BUG PANIC!
The game is also available as an in-game unlockable in CAVE's first Visual Novel, Instant Brain (although the game is a region locked JP Xbox 360 release), however, it is a condensed version only spanning 20 stages out of 50. With the Spring and Summer areas and Mendou (St.10) and Nakamura (St.20) as stage bosses. This version uses optional Kinect support.
As of 8/2/16, the XBLA version is now backwards compatible on the Xbox One.
This game provides examples of:
- Bullet Time: Happens whenever NIN-JA is close to an enemy outside of ninja-power-mode, or gets hurt.
- Chaste Hero: NIN-JA did not abscond with Sakura because he is a respectable ninja.
- Conservation of Ninjutsu: The enemies should have known better than to all become ninja.
- Enlightenment Superpowers: Namakura's powers probably are a result of him being a ninja Buddha.
- Eternal Engine: The Castle ninja world
- Gotta Catch 'Em All: The ninja scrolls, required to be a super awesome ninja.
- High-Pressure Blood: The results of NIN-JA dying are very messy. There are even detailed ninja fluid physics for his ninja blood.
- Hoist by His Own Petard: Fujiyama is defeated by his own ninja poison clouds.
- Mendou is defeated by letting him get hit with his own ninja meteors
- Hot-Blooded: NIN-JA
- 100% Completion: Finishing the whole game on S-Rank and getting all the Cave ninja items.
- Idiot Hero: NIN-JA is portrayed this way.
- In Case You Forgot Who Wrote It: There is a collectible Cave ninja item in every single stage, even the ninja boss stages. The children in the audience will also scream at NIN-JA to collect the Cave items. There is even an achievement for collecting every single Cave item.
- Ninja Pirate Zombie Robot: The first boss, Fujiyama, is a ninja version of Mount Fuji with arms and legs wearing a ninja bandana and who has the profession of assassin. He erupts poison clouds that he is not immune to.
- The second boss, Mendou, is a ninja kendo master assassin who can do the Razor Wind technique (with a kendo stick) and summon meteors
- The third boss, Oideyasu, is a ninja geisha assassin who floats around and throws fans
- The fourth boss, Yokoduna, is a ninja sumo assassin who shoots miniature ninja sumo
- The final boss, Namakura, is a ninja Buddha wizard president party-leader kidnapper - yes, that's right, a ninja Buddha
- Nintendo Hard: Notable for being a platformer developed by Cave that is still this ninja-difficult.
- Power of the Void: Namakura inserts the phrases "Emptiness is the form" and "Form is the emptiness" into his normal ninja speech. He appears to be a Zen Buddha as well.
- Pun: "Fujiyama" for Mount Fuji, "Mendou" for Kendo, "Oideyasu" for Oiran, and "Yokoduna" for Yokozuna.
- Rank Inflation: This game uses the ninja S-rank.
- Razor Wind: Mendou can do this with a kendo stick. It may be a ninja kendo stick, but still...
- Save the Princess: The plot of this ninja game.
- Scarf of Asskicking: NIN-JA wears a very long red ninja scarf.
- Shinigami: One, named Death, appears if the player takes too long to finish a stage, as well as during the normal course of the Castle world. And, in the score attack stages, many of them will eventually appear.
- Tennis Boss: Oideyasu, Yokoduna, and Namakura are all effectively ninja tennis bosses.
- Timed Mission: When enough time passes, Death appears. Take too long, or don't take the most optimal ninja route in the Castle world, and multiple Deaths appear. And, of course, the score attack stages have ninja time limits if the sheer number of Deaths don't get you first.
- Video Game Cruelty Potential: One of the things that NIN-JA screams upon getting hurt roughly translates to "Stop it!" Therefore, it is possible for the player to purposely get him hurt and killed, and he would be a Fourth-Wall Observer who is powerless to save his ninja self.
- Youkai: And they're all ninja Youkai, no less.