The making of Cult of the Lamb: 'A lot of the design was trying to encourage the player to be evil'

In a typical run-based dungeon crawler, at certain points your progress is blocked until you earn a tool like a grappling hook or a bomb that knocks down walls. In Cult of the Lamb, you don't unlock a single boomerang or even a double-jump. Instead, you brainwash more charming woodland creatures into devotion, then unlock the ability to convince them they go to a better place when you sacrifice them for dark power.

Maybe a better comparison is Stardew Valley, which does have a mine full of slime monsters.