GOG Linux version installed through Heroic -- fails to launch through Heroic in game mode (works on desktop) no matter how much tinkering you do on Heroic settings.

Added as non-Steam game, pointed executable to native binary (not GOG launch script) and forced Steam Runtime in compatibility settings.

I have a previously installed lib32-glu through pacman on read-only partition, so I'm not sure if this made a difference.