Fez plays sort of like Super Paper Mario, but with more of an emphasis on optical illusions. It appears as a 2D sidescrolling platformer most of the time, but at any time the player can rotate the entire world 90 degrees along a vertical axis. This allows the player to use optical illusions to navigate the game world. For example, Fish climbed a ladder up the side of one platform, and then rotated the world to reveal another identical platform several yards away. By rotating again, the perspective shifted such that it looked like the ladder was connected to the second platform -- and so it was, and Fish emerged atop the once-distant platform.
In another example, Fish tossed a bomb onto a moving platform to expose the entrance to a cave. He walked to the entrance, and then rotated the world 180 degrees to reveal the other side of the rock structure into which the cave had been cut, granting him immediate access to the other side.
When Fish paused, we noticed a "leaderboards" item in the pause menu. We don't know as yet what the leaderboards will compare, but at least they'll be there.