I found a game breaking bug.
After finishing the game completely and getting every scene, if you go to the library and talk to the dean's daughter and give her chocolates, she jumps from 4 hearts to 5 hearts (no new scenes sadly just the number of hearts going up) but after doing so you will be unable to save your game at all. You will get an error / rollbak screen stuck forever no matter what actions you do or where you go after you can't save game anymore neither idle, in your apartment, any location or inside scenes.
I haven't tested if this happens before you finish the game 100% but I suspect it breaks the game as soon as it happens. Perhaps she was never meant to go up to 5 hearts.