Flappy Bird and all of the clones that came after it was a while ago now. I'd almost forgot about it. But then Flappy Defense popped up.
To clarify: it's not a clone of Flappy Bird. It does, however, use "Flappy" in its title, and also features flappy birds and green pipes.
It's actually an action-based tower defense game. The idea is to keep a whole flock of flappy birds back by shooting them with a cannon.
If you have any pent-up anger or frustration left over from playing (and failing at) Flappy Bird then perhaps this is a good way of letting it out.
As you progress, blasting the bird bosses down, you earn diamonds to buy extra and more powerful cannons.
It's also on itch.io if you want to play it on PC.