After playing the game, I'm interested to see if Takeda sensei will include a way to save the girls from corruption. I mean, of course, there's already a good ending, with no CG, if we save the girls ASAP and defeat the demon king. However, after the beach event and getting house arrest, we were given 20 days to roam around and see the events unfold.
Yet there are ways to counter the corruption or stop it before it gets worse. There is this segment where Kurt is talking to a shop owner and he needs to investigate a few things to find out what's going on and to prove his innocence. There's also the Siren church where you pray to lessen the corrupt state of the girls. Maybe with this, the variation of the endings will change.
Also in the recollection room, on the top right, there are more events for the girls. They're not implemented yet, but since the bottom half of the recollection consists of the 1st half, 2nd half, and sub-events, I'm curious what those events will be.