Pantheon: Rise of the Fallen is apparently hard at work following the release of the game's most recent update video. A new dungeon preview is available on the game's Facebook page, showing off a single in-progress screenshot and discussing the design principles behind Amberfaet, the Kingdom Underneath. It's not mentioned exactly what it's underneath, which leads to the inevitable conclusion that it lies buried deep below the ancient drive-in movie theater. Or some surface ruins; who knows.
Amberfaet is proudly held up as a sprawling dungeon containing content for mid-level players all the way to max-level raids, with a great deal of time within dedicated simply to navigating the crumbling ruins up and down. OSHA compliance is apparently not a standard feature in the Kingdom Underneath. There's a bit more information on the official preview, if you're so inclined.
Pantheon began collecting donations through Patreon in November following the collapse of its initial funding and paid development team last spring.