Core Keeper is celebrating a major player milestone alongside the announcement of its next big content update. Pugstorm and Fireshine Games have revealed Riders of the Underground, a free update launching September 21 on PC and consoles, while also confirming that the mining adventure has surpassed 6 million players.

The biggest addition in Riders of the Underground is the ability to ride mounts for the first time. Core Keeper’s friendly cattle can now be ridden around the underground world, with the creatures also receiving new behaviours that allow players to tell them to stay in place, roam freely or simply follow along as an adorable companion.

Exploration is also getting a new option with the Hookshot, a grappling hook that lets players cross chasms and pits without having to build paths or bridges. Meanwhile, the Forgotten Ruins are expanding with the new Moss sub-biome, adding lush greenery to its otherwise stony surroundings.

The update also brings multiple new pets with their own abilities, along with new weapons, accessories and armor pieces. A selection of quality-of-life improvements will round out the free update.

Riders of the Underground launches September 21 for PC, Nintendo Switch 2, Nintendo Switch, PlayStation 5, PlayStation 4, Xbox Series X|S and Xbox One.

Players attending Tokyo Game Show later this month will also have the opportunity to get an early hands-on look at the Riders of the Underground update.