I found a glitch that allows you to unlock gallery scenes without reaching them I watched a few gallery scenes then hit return but instead of going back to the menue I got to watch a gallery scene I hadn't seen yet and then that scene was unlocked I had to close the game to get it to stop opening more scenes everytime I hit return I wouldn't mind it if you kept the gallery unlocking part of the bug in just get rid of the softlock part. Its a good thing I saved before I did it
(edit I was able to reproduce the glitch easily it goes through every gallery scene after the one you watched)