For all the talk of Mario, Rayman, and Donkey Kong... you guys have the wrong genre. @_@
Ori and the Blind Forest is a 2D Action Platformer (or even a Platform Adventure... but most call it MetroidVania), which is very different from a pure platformer. Think of the title more akin to games like Super Metroid, Castlevania: Symphony of the Night, Guacamelee, and Cave Story. The game hosts an interconnected world in which you can gain new abilities as you progress, allowing you to access areas you couldn't before.
That said, both genres are among my favorites, so I'm ecstatic either way. 