Hey snackaholic ;D,
The clone cost me about 2 hours, but usually it takes longer because I've already prepared all the assets in this video(Spritesheet, Sounds, Fonts, ...).
I learned game development with LibGDX with the internet(YT Tutorials, and a book).
It took me about half a year to be able to use LibGDX to program a game like FlappyBird on my own.
LibGDX is a bit more complicated to learn than most other Java Game Frameworks, but it's faster.
That's why you also have some advantages when you acquire LibGDX.
I've already thought about doing some tutorials on LibGDX in the future, but I think I will not have enough time for it.
But if I'm going to do such tutorials on LibGDX, I'll send you a private message.

So thank you for your feedback.
LG UbuLin ;D