Thanks for the feedback! The game does limit when you can open your inventory (can’t open it during cutscenes, for example) but it’s totally possible I made a mistake and left some open loops, you might call it. I’ll check a look! If X/Shift doesn’t work for the item inventory, please, do use escape to open the pause menu and select “ITEMS” from there for the time being.
As for the piano section, you do have to listen to the melody in full, and then try to repeat it by ear fully. I understand that this puzzle in particular is difficult for some players, so that will be addressed in a bigger patch to the demo (1.1 - ETA June-ish) which will also introduce some content that was left on the cutting room floor to make a deadline.
Once again, I highly appreciate the feedback! Hope you manage to finish the demo :>!