In late July, Meta introduced a hero shooter called ‘Super Rumble’ to Horizon Worlds, aiming to improve user retention on its social VR platform with the promise of higher quality first-party content. Now Meta released its second big anchor minigame on Horizon Worlds, a co-op adventure game called ‘Citadel’.

Citadel is what Meta calls a “rogue-lite action-adventure puzzle platformer FPS,” offering up both solo and co-op play.

Here’s how Meta describes the action:

Combining combat, puzzle-solving, and skillful gameplay, each room in Citadel gives players a new challenge to overcome. With numerous hidden secrets to uncover across 30 rooms, Citadel offers a wealth of content to explore. And after completing the game in Casual mode, those up for an additional challenge can take on Veteran mode for an even greater sense of achievement (and additional bragging rights).

As you infiltrate the citadel, find hidden relics, and eliminate enemy forces, you’ll unlock weapons and rewards and earn credit to buy new armor with unique stats to upgrade your hit points, number of lives, and speed. Mix and match helmets and torso armors at will to fully customize your gameplay experience.

Stocking Horizon Worlds with higher quality content has only been one piece of Meta’s user retention puzzle. Back in April, the company announced it was set to officially open the platform to kids ages 13+. Meta has also recently begun a closed beta for Android users, opening the platform to non-VR devices for the first time.

The company says it’s hoping to open Horizon Worlds to iOS devices and standard web browsers too at some point, which could help the platform gain greater traction amid some already fairly fierce competition. This comes as Meta opened Quest up the online gaming powerhouse Roblox, joining popular social VR platforms Rec Room, VRChat, and Gym Class on the Quest platform.