In PaperPlane, you control a paper airplane, which emerges from a treehouse on the hill. About it is a fairly drab rural landscape, but sparkles show near certain items in the scene -- a swingset and a tire swing, for instance. When you fly through a sparkly area, two things happen: First, new content unlocks, making the landscape less drab and showing people and animals moving about and enjoying the countryside; and second, for a time your paper airplane gets "jets" that allow it to move faster and regain height.
Ultimate, you repopulate a prettier landscape with life; there's no score, but the implicit goal is to keep flying as long as possible, and unlock everything available.
The basic problem with the game is the difficulty of the controls; while the left-and-right arrow keys allow you to bank and turn, there's no pitch control. The pitch of your craft seems to be controlled indirectly, by how you bank -- turning, you seem to stay aloft much longer than simply flying straight, when your nose inevitably drops -- but even after a fair bit of experimentation, it's still frustratingly difficult to control your craft.
If the UI is obtuse, however, the graphics and soundscape are both lovely; the music reminds me a bit of that from The Snowman, an animated film likewise based in the countryside (and this is, by the way, high praise).
PaperPlane is a 2011 IGF Student Showcase Finalist.