Really nice puzzles, both the puzzle process and artstyle remind me of old flash escape room games i used to play over and over again~
The cypher puzzles themselves are fun but I'd prefer if they were more related to other puzzle solving elements like the map and clock puzzle at the beginning rather than straight cypher grids at the end. The QTE and non-standard grid at the end were nice additions though, and I did like them too, though I was a little surprised the demo ended so quickly on a comparatively "fast-paced" note.
The password feature to return to certain parts is very on brand for what the game is, but at the same time I wonder if a chapter select after completing the required section/finding the required password wouldn't be more convenient. I realised at some point I really only commit the latest password to memory, which is fine for progress but not as great if I wanted to revisit older puzzles. The same would apply for the new spicy pics.
TLDR: Other supportive puzzle elements nice, chapter select not a bad idea. Good game.