I should also mention that I tried game versions 1.63.9 (DRM-free) and 1.64.0 (the latest version on Steam). The game is also on Humble store
, which should be a newer version, though I can't get it at the moment.
Update: Finally got the game from Humble Store, and unfortunately, it's still 1.63.9, so the lighting issue is still relevant. Any help would be appreciated.