This is very, very cool! I had to use the guide at the beginning to figure out what to do, but I ended up getting all 26 letters! The puzzles were very creative, and it was a lot of fun once I started to get the hang of it!
The only thing I'd suggest is adding a back button from the ending because I accidentally triggered the ending multiple times. Including AFTER I collected all 26 letters, and I do not have the patience to try for that ending again lol. I'd personally suggest a back button option both when you go through the questionnaire and when you reach the first ending.