I really liked that you added "flappy bird" mechanics, even though the hurdles already had enough of content. But small additions like this one make the game so addictive.
Every round has a unique feature that makes it challenging and rewarding: hurdles - flappy bird mechanics, hammer - very narrow window to let go and bushes on the way that you need to avoid, long jump - a stone that I didn't manage to avoid, but if you fly close enough to it you can get like 4.6 or something, high jump - the initial positioning is very important because if you manage to stay in the center and jump straight up, you can get like 6.2.
Overall this game is an amazing experience, extremely addictive, every level is thought through and very polished.
Quack!