Dust is a beautiful and odd little game, and is, unsurprisingly, a student showcase finalist for the 2012 IGF awards.
It's a sort of sidescroller, in that motion is left-to-right, along a linear path, but the gameplay is not what you'd expect from a typical sidescroller. You are a moth, hovering in the air, and move with WASD; you are trapped in an attic, and can see the moon glowing outside. As you move away from the window, the game teaches you that you can revive dead moths if you get close enough to them; they then follow you about, and can push objects. Sometimes, you need them to do so to move obstacles out of the way; other times, you need them to push an object into a cobweb to clear a path. Movable items are marked with numbers, indicating the number of revived moths you need to move them.
If you fly into darkness, however, you "die" (actually, you're sent back to the last checkpoint, so this is not dire). But scattered along the path are light-producing items -- candles, a flashlight, lanterns, and so on; and when you are sufficiently near to them, you can turn them on, to extend your range further.
In other words, the game is a series of navigational puzzles, and not trivial ones; even though you may know that an item needs to be moved, it's not always clear in what direction, or how. The controls are a little awkward, particularly in that sometimes you are both moving yourself with WASD and your moth companions with the arrow keys; and it's hard to position optimally, sometimes. But it has a strong, almost haunting feel.