A Lite [free] version of 1-Bit Ninja has just hit the App Store. Despite the fact that it's a precision based platformer, the game actually works incredibly well considering the touch-based control method, and hearkens back classic monochrome graphics that give homage to the original Mario Land. The night that I bought the game, I played it for a pretty solid few hours -- not bad for a game that came out of nowhere.
In addition to standard platforming, you'll be able to fiddle around with the game's camera to look for hidden areas. The Lite version will allow you to play the first five stages, but given how good it is, I expect you'll just pony up the requisite $1.99.