This is Owlboy. It's a game from D-pad Studio. This is their description of the game:
Owl Boy is a 2D platforming adventure for the Xbox 360 and Windows PCs. Go with Otus on a free flying quest into the clouds and discover the secrets of the floating islands while preserving the Owls' integrity...Pretty much sums it up. Good news is it looks pretty great! Better news is it's being entered into the IGF , so hopefully it can pick up a little more exposure while it's there.