The demo of Return of the Obra Dinn (GDC Demo Build 0.1.23) is available for free on Lucas Popes' website.
In the latest demo build, the inspector receives a Crew Muster Roll Book of the ship rather than the book of surgeon Henry Evans as in the release version. The player would have to find it inside the ship instead of having it right from the beginning. Crew listed is slightly different from the release version, and pictures and chapters of the game have been added. The inspector is referred to as an agent, and has a legible name, Edward Grenstal.