Out of curiosity I asked Raw Fury about information concerning a Linux port and got the answer:

   "Our plan is to support Linux on GOG as well as on Steam:
    Build has been doing good in testing,
    I will make sure we update our store page with this information.

    All Raw Fury titles are tested on Linux as well, even if we sometimes cannot do a port the game,
    we always test it at least via the Steam proton compatibility layer and see if it works good there."

So a native Linux port may emerge on GOG eventually ...

The negative trend thinking that Wine/Proton is sufficient on Linux is forced by Steam and
other platforms no longer asking for native ports.

I don't think this is wise ... and when capacities are not there a game engine
with good cross-platform support is a much better solution than a mapping/emulation
for an engine which may not play well with the underlying HW.

When people playing under Linux only they will soon get the difference - especially if the game
was developed under GNU/Linux.

So nice that here a Linux port is in the making ... I may get the sequel when it is available on GOG.