2D platformer in which grabbing is the primary mechanic. You grab, you throw, and you shake stuff and see how every enemy, projectile, and object reacts (they almost never do what you expect them to).

It has some low points in the later levels, especially in the second part of World 4, but goddamn, the highs are incredible. I'll be remembering that final battle for the rest of my life.

Innovative on every level, silly when it has to, and consistently enjoyable from start to finish.
And, at least for me, that's what video games should be all about.