Thank you for your kind words! The linux test build that I run in a VM sounds mostly like the Windows version does, there's only a noticeable audio delay (probably the VM) and the frame rate is a bit low, so that the drum rhythm is a bit off. I plan to install Ubuntu on a USB stick soon to test how it performs on my real computer.
There are two build options for Linux, one of them should have a better performance and would be preferable, but doesn't seem to work right now. Looking in support boards showed that other devs have the same issue at the moment. Maybe a bug in the game engine, maybe a recent update for a required Ubuntu package that made it incompatible, not sure. Anyway, I'll see what I can do!