One More Dungeon is a first-person shooter roguelike game that features procedurally generated levels and pixel-art graphics. The objective of the game is to reach the final level of the dungeon and destroy the obelisks being used by the forces of Evil to invade the world. As an anonymous adventure seeker, you must use a melee weapon, magic staffs, and antique artifacts to fight your way through the hordes of enemies inhabiting the different game areas.

The game is a fusion of old-school FPS and roguelike games, with permadeath and procedurally generated levels that make each playthrough unique. There are over 30 types of enemies and 80+ items to collect throughout the game. Additionally, there is a parallel universe with manually created locations that players can access. One More Dungeon features a sanity level which is reduced by using artifacts, and a set of mutators that players can select before starting the game to modify the gameplay.