FWIW I witnessed a friend of mine playing Mewgenics via Proton on his Arch desktop. Seemed to work fine. So, only Windows-only to the usual degree, it doesn't seem to have any sort of problematic DRM or anti-cheat to worry about.
Binding of Isaac runs great via steam/Proton haven't even thought about if its native Linux or not.
Binding of Isaac runs great via steam/Proton haven't even thought about if its native Linux or not.