It wasn’t on proton but there’s a very old entry on wine. Looks like my boy Jeff’s last entry was quite recent in 2023, he rated it a silver. There’s a known bug from some graphical glitch during certain events like the protagonist meeting himself back in time and others which may prevent completion. I wonder how it works now, tempted to test it out.
Also, I’m more confident that old games will work out of the box from gog than Steam. Unfortunately, as a Linux user, out of the box proton supports on Steam is just too convenient. I can’t think of many gog games that natively run on Linux.