FNF Rhythmic Revolution

You can play FNF Rhythmic Revolution online for free right here; the whole game runs in your browser tab. Play it with the sound on — the audio isn't decoration, it's the actual timing information.

Grab your keyboard and mouse and you're set; there's no settings maze to fight through first. Playing on a phone works fine here; the game adapts to touch without complaint. Hit the fullscreen button and the browser gets out of the way entirely. Worst case, you lose five minutes finding out it's not for you. Best case is considerably longer.