Lighting inside the buildings on Myst Island doesn't work at all inside the clock tower, cabin, power room, tower, planetarium, and is extremely dim inside the library and imager room. I've submitted a problem ticket and since added a reply to it with more specific info. No response to my tickets.
I'm using Windows 8.0 x64 with an ATI Mobility Radeon HD 4250 graphics adapter (AMD). Tried Advanced video settings in realMyst eliminating all features, some features, features "on" one at a time, etc.; no change. All drivers, OS updates, realMyst updated (using Steam).