http://gettie.i2p/posts/osu-on-linux.html
You can use it in most operating systems. There are binaries for Windows, macOS, iOS and Android right now. It's not stable enough to use yet, as there are still bugs and some missing features. The best thing is that because it's running natively on your system instead of using a compatibility layer like Wine, on Linux you can use ALSA instead of PulseAudio to play with as less latency as possible (There is also a bug if you try to use PulseAudio).