Players once again take on the role of the Doom Slayer who battles the demonic forces of Hell, from a first-person perspective. The game continues its predecessor's emphasis on "push-forward" combat, encouraging the player to aggressively engage enemies to acquire health, ammo, and armor. The player has access to various firearms, such as the Combat Shotgun, Super Shotgun, Heavy Cannon, Rocket Launcher, Plasma Rifle, Chaingun, BFG 9000, Ballista, and the Unmaykr. Melee weapons such as a chainsaw, the "Crucible Blade" energy sword, the Sentinel Argent Hammer (Hellbreaker), and a retractable arm-blade called the "Doomblade" can also be used. The arm blade provides the opportunity for a larger variety of quick and violent "glory kill" executions, which drops extra health. The Super Shotgun is now equipped with the "Meat Hook", a ranged accessory that grabs onto enemies and slingshots the player towards them, functioning as a grappling hook, useful both in combat scenarios and environmental navigation. The Doom Slayer's armor now includes a shoulder-mounted Equipment Launcher with the ability to lob grenades and ice bombs. In addition, there is the Flame Belch, a flamethrower that sets enemies on fire with it to drop armor pickups. Finally, killing enemies with the chainsaw will drop ammunition.[1] New movement mechanics such as wall-climbing, dash moves, and horizontal bars to swing from have also been introduced.[2][3]
Like its predecessor, Doom Eternal invites the player to develop simple tactics. As the game gets harder, the player needs to use the advantages of fight arenas, and their bonuses, in more strategic ways. They also need to decide which enemy has to be killed first and how to move on the battlefield.[4][5][6]
Creative director Hugo Martin has stated there would be twice as many demon types as in the 2016 reboot. There are new types of enemies, such as the Marauder and Doom Hunter, while others, such as the Pain Elemental, Arachnotron, and Arch-vile, have been reintroduced from previous Doom entries. A new system called "Destructible Demons" is featured, in which enemies' bodies progressively deteriorate as they take damage. Through this system, certain parts of a demon's anatomy can be destroyed to eliminate their ability to use their stronger attacks. There is also a new life system. During gameplay, players can collect 1-up items (which look like green helmets) scattered around the environment. When the Doom Slayer perishes in combat, he will respawn where he died, instead of restarting at the nearest checkpoint.
The game features several asymmetric multiplayer modes, including Battlemode. This game type is a 2v1 PvP multi-round match where two player-controlled demons take on one fully loaded Slayer. There were five playable demons at launch, with more to be included in free updates post-launch. The current six available demons are the Marauder, Mancubus, Pain Elemental, Revenant, Arch-vile, and Dread Knight. In addition to regular attacks, each demon has a "summoning wheel," which contains a selection of four additional abilities. An additional mode, Horde mode, was released on October 26, 2021, as a part of update 6.66.
Also new to the game is the hub area, called "Fortress of Doom", which players can visit between missions, containing a number of rooms with upgrades and gear locked behind doors. Players can also unlock a bonus weapon, the Unmaykr, after clearing six challenging Slayer Gates.[7]
