It's rare that we preview these block-drop/puzzlers, since they typically play better than they look -- but Unify looks pretty great already:
Instead of a single piece falling from the top of the screen to the bottom, two pieces move in from the sides towards the middle, simultaneously. The goal of the game is to make combinations of 4 or more of the same color, so that they disappear.
Once blocks disappear, all the blocks on top of them move in towards the center, giving you the opportunity for combos.
Gage had also sent in a video of a 3D audio concept game called "Face It" designed to be used with the iPhone 3GS's compass. He recommends you use headphones to listen to this video as it otherwise won't make sense.
No word on when Face It might make it to the store, but Unify is already well into the approval process.