so no big slime girl to capture , you got idea what is wrong?
edit :
added the save file of the game to it
Besides everything mention already the jar, interacting with the magic circle and fire holders you have to go to the church at night and read a book on the shelf closest to sister Elizabeth's bed that tell you about the slime needed to be used on the circle. You could go in the day if she is in the back massaging her breast but that is limited to some day at some time so night is easier as she will not let you back there unless she is outside of the church.
*edited* I checked with my first save (save at start) she is only missing if you don't interact with the magic circle in the basement which allows you to interact with the book in the church, the jar is needed to collect the slime for the quest and can be bought at the shop for 30 gold or gotten off of Krowly's table for free.
The book in Krowly's house is most-likely information that allows Krowly to cum in the jar during masturbation during sleep segments after he gets the slime from the busty slime in the cave that you are looking for.
How win Green jelly?
Как победить зелёное желе?
Get some hp potions fight it normally it will spit you out when it engulfs you if you have the slime terror necklace on which works just like the slime repel potion but its effects don't stop until you remove it, Lizzy will not be able to interacted with you in open world and possibly not in battle when wearing it, but all normal slimes leave you along.
