i haven't seen anyone mention it, but after seeing the water connecting to the vents inside the castle (first screenshot) and unlocking the swimsuit, i figured you could sneak inside the castle thro the vents by swimming from the outside. I saw the swimming interaction once i put on the swimsuit and was pretty excited about it but other than swimming around there and to the bridges north and west there's not much else to do, no idea how to actually get in this way (or if it's even possible). Anyone knows?
sa
EDIT: Also one more thing i was curious about, after completing the worm girl quest you receive 3 quest items, one to give to the spider, one to zombie girl and one to give to "Security Guard Succubus" (3rd screenshot). I've talked to every single succubus in and outside the castle and still found no one to give this to so i was wondering.