I feel like there could be more clarity in a lot of places. It's fun to explore, but given that's it a demo, I'm not sure how far it has completed (as of yet).
Spoilers:
The game asks you to find something long and I am not sure what exactly constitutes for it (for the fountain). I am aware of the train contents and it is very interesting to follow the tunnel to see the 'night time' part of it, but not more (besides observing that there is a staff room that I cannot enter). So far I have 3 souvenirs and that is it. I am also aware of the place which looks abandoned but cannot access. I'm not sure what to do or if it's fleshed out or if I cannot access as that's not completed yet.