Just didn't launch at all for me on Linux Mint. Also, I noticed watching a video that the title screen is different for me. I thought it looked kind of weird.
Woah, that’s strange. Are you running it under Wine?
It looks like the color components are messed up on the title texture, maybe due to how I’m drawing it (in color tinted strips for the fake 3D). The other colors all look correct at a glance.
I haven’t had a chance to look at this yet but my hypothesis is that I’m not actually clamping the component value to 255 there, and it is is probably wrapping when it narrows - not sure why it only appears on Proton though.