This was a hilarious reversal of flappy bird - one of the more creative ones I've seen! The art was also excellent, and I like the choice of a very limited, muted color palette. Also enjoy how it's easy at first, and then by the end I'm like "Oh no, the horde! Smush them! No, stop bouncing off the pipe!"
Agree with the other commenters that some music/sound effects would be good and make the game feel more complete. Otherwise it's a simple but excellent game :)