Heart: The City Beneath is a standalone roleplaying game that gives players the opportunity to take on the role of delvers people on the fringes of civilization who are driven to explore a shifting, unpredictable realm waiting beneath the surface of the world in search of answers, absolution, or revelations.

Using the Resistance System first developed in Spire: The City Must Fall, Heart focuses on what player characters have to lose in pursuit of their goals -- whether that's supplies, friends, sanity, blood, a way home, or spatial or bodily integrity. Anything is up for grabs. Classes such as the addict Junk Mage, the bee-filled Deep Apiarist, the ravenous Cleaver and the pre-deceased Deadwalker give players the opportunity to explore the world from unique perspectives.