Like Canabalt and other "runner" games, the simple aim of Yoo Ninja! is to keep going for as long as possible without coming a cropper. There's only one control – a tap of the screen – with which you flip gravity on its head, allowing your little ninja to stick to the ceiling as firmly as an unwanted piece of macaroni in the school dinner hall.
Should you time your taps badly, the little warrior will either plummet to his doom or float off to the big dojo in the sky.
What is he running from? We're provided with no backstory, but an ever-present pair of dicing, slicing throwing stars criss-cross the left side of the screen provide a clue to his motivation. Should he get stuck or slow down too much, he'll be ninja Julienne in an instant.
The in-game music races along with the action, much of the time sounding strangely like a DragonForce cover with flutes. In no way is this a bad thing.
In keeping with the straightforward nature of the game there are just two modes. Story mode takes you through a variety of different level and obstacle styles with checkpoints along the way, while Endless mode tests your staying power as you go for a high score, much like Canabalt's standard "distance travelled" scoring system.