[dmarlow]

Great work. The examples are fantastic. Code looks really clean, but there's quite a bit of magic going on that's not immediately understandable. For example, in the flappy bird clone, how are the pipes' placement determined?

[ticklemyelmo]

The playfield is a moving camera view on a static world.

The bird moves forward constantly, the camera follows the bird, and the pipes spawn at a fixed location one screen width ahead of the bird.