i think this is the game you have with the most potential. you could expand into the toilet for special/more advanced scenes. you could make tentacle walls set to another button like alt that prevent girls from entering the area and from running away. you could make possessed girls that rape others. you could make limited, placable auto capture lockers. girls could start walking around naked when their count is high enough. you could lvl up the tentacle monster to increase speed and attack with multiple lockers at once. add more girls and teachers. hell is the limit, get creative, dig deep
also it would be nice to know exactly what you get from raising the stats and how much there is left to get.