Dokuro was first released in Japan and other Asian territories on July 5, 2012. It was later released in North America on October 16, 2012.
The game takes place over 15 worlds with 10 stages each. As the game progresses, each world introduces new abilities for Dokuro to use and new mechanics in the levels. The crux of the gameplay is straightforward enough: safely escort the nameless princess from the start of each level to the flower at the end. The princess has a small modicum of intelligence, and basically walks forward until there's a ledge or fall she can't traverse, and will also attempt to turn back and run away if there are any monsters in her path.
So, it's to you as Dokuro to help her through. In true 2D platformer fashion, there are various obstacles such as spikes and enemies in the way, as well as levers tied to moving platforms, things of that ilk. Dokuro can also move crates and boxes. As the game progresses, new mechanics such as gravity-flipping switches will make things even harder.
Your best time for each level is tracked, as well as whether or not you obtained the coin hidden away in each level (both of these things are tied to the game's trophies).
As the game progresses, Dokuro will gain some new powers: the power to transform into a prince for a limited time, and various chalk-based powers (which fit in with the motif of the game's charcoal-rubbing art style).
By using either the Vita's rear touch (or simply the R button), Dokuro can transform from his skeletal form into a prince for a limited time.
The main advantages this provides is that the power of his attack increases (he uses a rapier to fight instead of a bone), and he can also pick up and carry the princess. The latter of these two benefits comes in handy often: expediting the princess to the goal, helping her dodge obstacles (i.e., weights trying to crush her from the ceiling). The princess can survive a slight fall, so it can be helpful for bringing her down from a ledge (since she won't walk off on her own). However, the prince can barely jump while carrying her, so going up ledges is not an option.
The one minor disadvantage of the prince form (besides only being able to do it for a limited time), is that Dokuro cannot double-jump in this form, but can while he is a skeleton.
Dokuro gains the ability to use various colors of chalk. These are used via the Playstation Vita's touch screen.
The white chalk can be used to make chains or ropes, and attach items together. The red chalk essentially acts as a fuse, allowing the player to use sources of fire to light candles, dynamite, or cannons. Blue chalk requires the player to draw a horizontal line across a pit, which will cause water to fill the pit up to the drawn level; this can be useful for making crates float, vines grow, or drowning enemies.