Similar to the story of Doom 2, the demons from Hell invade Earth. According to Id Software, they hoped to expand the Doom story much more than in the earlier Doom games. Places where the player goes include Earth, Mars, Phobos (one of Mars's moons), Sentinel Prime, Argent d'Nur, Nekravol, and even the game's version of Heaven, Urdak. Some of these planets have been taken over or are being taken over by the Hell dimension.
The monsters and weapons have been redesigned so that they look more like the ones in Doom and Doom 2. Each weapon received new attachments, so they play differently than they did in Doom (2016). The game also added new mechanics like extra lives, wall-climbing, air-dashing, swinging from monkey bars, and swinging from grappling hooks. The player also received a flamethrower so that they can gain armor points when they damage inflamed enemies. The game is designed where certain body parts of the demon enemies can be damaged, so attacking and destroying those body parts can disable certain attacks and make them easier to kill.
The game is designed to be much more difficult than the earlier games because the player has much less ammunition and the enemies are more aggressive.
The game has multiplayer like its prequel, but there is a new mechanic called Invasion Mode where players can play as demons and invade other players' campaigns to kill them, though Id Software said that players allowing this feature in their own campaigns would be up to themselves.