Press space to flap your wings, and don't hit the edges. This is meant to be more an animation than a game, so yes, it is super easy. Consider it a test of patience / ability to do something completely unproductive for an extended length of time. I'm a lot better at art now than I used to be, so I'm considering redesigning the graphics.
UNPLAYABLE ON MOBILE. Thank you to the Deviantart people who posted flying animations. I used them as references for anatomy.