Item combinations remain the real rabbit hole. One seemingly useless pickup can suddenly bend an entire run in a new direction, and whatever comes afterward keeps nudging the build somewhere stranger. Alternate routes and new bosses add more uncertainty, while the hidden stuff gives curious players plenty to uncover. The full version is unlocked.
The sheer amount of content is impressive, but the lasting appeal comes from how the pieces interact. Shuffle the same characters, rooms and rules into a different run and the result can feel oddly unfamiliar again.