I just finished a bug I noticed while building level 4. this was if you pressed new game after dying it did not reset chapter 2 and 3 key flags meaning that the key counter never rose. Below I am going to show my current progress on chapter 4

there won't be many keys in this chapter and each of the ladders will be unlocked as you progress through the level. the upper section will be unlocked at start and each path above unlocks a path below. the top path hazards are utilizing the new form that peryil obtained in the last level. the middle path (lowest path in the image that has completed rooms) has a projectile defense grid. the bottom path will be a slime creature. who worked for a cult. can't give much more. as that will be a severe spoiler.