I'm just getting started with C# and using for the moment Unity to make it more interesting.

As a kid I used to play an old jetpack joyride type of game in one of these bad boys (not exactly that one but you get the point). It stuck with me because it was so fucking good, so much fun that I want to replicate it now that I'm learning.

It worked like flappy bird, you need to tap a button to stop gravity from crushing you against the floor, but at the same time you need to avoid crashing against the roof (don't tap too fast!). This is why looping a background like flappy bird wont work, it needs to change and get more dificult over time otherwise you are avoiding the same floor roof combo every time.

Should I do 2/3 long-ass backgrounds and then stitch them together or is there a better way? Maybe I don't need the background to get radically harder, I can just make the "bird" go faster over time until its too hard to watch your way...

TLDR: background needs to loop indefinitely but also change over time with different "obstacles" (roof floor), I'm a noob so keep that in mind.

EDIT: also while you're here if you have a favourite free-to-use 2d assets page or forum I'd appreciate it.