There are many alternatives to osu! for Mac if you are looking for a replacement. The best Mac 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 Mac so hopefully you can find a suitable replacement. Other interesting Mac alternatives to osu! are Frets on Fire (Free, Open Source), Clone Hero (Free), Friday Night Funkin' (Free, Open Source) and Quaver (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!.