Just a fun little idea I had for a potential (harder) mode: Shrunk Mode.
Player is half the height of the normal model, moves slower, and can only carry one item at a time, but has greatly increased "stealth", meaning that Bella has to be a lot closer than normal to see you, and she'll prioritize eating your similarly smaller classmates she sees from the get go, but also has a greatly reduced hunger cooldown because you're all just apples to her and it would be easier than usual to stuff you all down her gullet.
Now some problems with implementing this aside from the fact you're doing this for free and have no obligation to add anything you don't want to is that since the player can't really look up or down, some item placements might be extremely hard to see/impossible for the tiny player model to pick up. And as I don't know how much time it takes for the fourth bell to ring, fine tuning the reduced walking speed so it's still possible to escape in time might take a bit of troubleshooting.