So yes, I have seen many comments about a section in Chapter 2 where you can wander outside the map through an unlocked door in the Private Study. Interacting the door was originally supposed to trigger a "cutscene," but I made a last-minute error in scripting before uploading the demo, and I didn't see the mistake.
That bug has now been fixed, so the cutscene happens like it's supposed to, and I have uploaded the new version of the demo. Along with this fix comes minor updates such as making a few puzzles more sensible and making one puzzle in Chapter 1 a bit harder, and minor map and lighting changes. Probably some other minor changes in there too that I've forgotten but are hardly noticeable.
Please visit the download section for the new demo; I've removed the old one so there will be no mistake.
I would advise you to start the demo over if you replaced the old demo before completing the chapter 2 puzzle. The jar you need for that puzzle has now been pushed back to chapter 1.