Not sure, previous Mac demos you have released in the past have worked for me. I think I have opened other games that were market builds that functioned, I don't know how much troubleshooting help I can offer.
So there's progress!
The saves from the demo should be compatible with the full version, but It's not supposed to go the other way around, as the script simply isn't there.
How buggy is the lighthouse?
That screenshot looks okay to me. That's what that display should look like at the start og the game.
