More lockers and add restroom/locker room and vending machines. Add swimming pool doors and a gym. This could add different outfits, like swim suits and gym uniforms. Adding more lockers, gives it more of a hallway of lust doom. In the vending machine, allow it to become corrupt and this will cause the girls that buy a drink from it to become less aware of others getting caught by cthulhu. And non corrupt vending machine, make the girls more alert. Not sure if these ideas have been suggested, I'm new here...
I loved the demo, then bought the full game, then became a patron. This is a fun game to play.