There are many alternatives to osu! for Linux if you are looking for a replacement. The best Linux alternative is StepMania, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 10 alternatives to osu! and five of them are available for Linux so hopefully you can find a suitable replacement. Other interesting Linux alternatives to osu! are Frets on Fire (Free, Open Source), Clone Hero (Free), McOsu (Free, Open Source) and Friday Night Funkin' (Free, Open Source).
Clone Hero is a free rhythm game, which can be played with any 5 or 6 button guitar controller, Game Controllers, or just your standard computer keyboard. Download the game, copy your song charts into the song folder and enjoy hours of fun!.
A free open-source circle-clicking rhythm game practice client for osu! beatmaps with Virtual Reality support. McOsu is developed separately from and has no direct affiliation with osu! or ppy Pty Ltd.