Now that you mention it, I believe you need to do a certain scene related to the study room before the interactable appears. I'm not sure if you need to catch every monster, since I was actively catching them all before progressing. Wish I could help you more, but it's been a few weeks since I played the game at this point. You could try checking the secret shop again, it stocks new items a couple of times as you progress through post-game.fuck... then it indeed bugged out for me it seems. ty for the info
my tower front door:
View attachment 4020013
or maybe i misinterpret how to end the game? i got all sex scenes in encyclopedia, so that should be all? (minus the study room one, but it says complete for all girls) Edit: nvm im stupid, obviously one is missing for leo
do i have to catch all monsters?