There are nine Doom Eternal Cheat Codes to collect, including one that’s not actually found hiding in a campaign mission. We’ll update this page once we find the others, so check back later on to see where to get them.
The first of the Cheat Codes can be found near the end of Hell on Earth. Walk through the corridor in the image below, and you’ll see a yellow question mark hidden behind a gate above you.
Continue walking down the corridor and take out any demons or tentacles that try to stop you. You’ll hit a junction in the corridor. Head right and climb onto the box next to you.
Look up for a vent you can break. Smash through it, crawl through the air duct and pick up the Infinite Lives cheat code.
Fortress of Doom
There are two Cheat Codes you can find on the Fortress of Doom. The first requires you to use Sentinel Batteries to unlock the Original Praetor Suit.
Once you have, head to the left where the wall has fallen apart. Jump out of this gap, spin around and dash onto a ledge beneath you. The All Runes Cheat Code is here.
The second can’t be reached until you’ve added Samuel Hayden to your floating home. Once you have, look for a small red target you can shoot in the same room as the Unmakyr container.
Hit that and a Grav Lift appears by the steps. Jump up this to reach the Fully Upgraded Suit Cheat Code. This activates all Suit Perks when equipped.
The next one is found in the Cultist Base. You’ll come to a room with spiky walls, and your objective marker will tell you to head down a gap in the floor.
Instead, walk around to the other side. Spot the question mark. You have to swing from one of the bars, spin around quickly, and dash into the gap to grab the IDDQD cheat code. This cheat activates Sentinel Armor for the whole mission it’s used for.
The Silver Bullet Cheat Code can be found in Doom Hunter Base. From the room shown below, jump up the platform at the end. Climb up the wall to your right, and jump to the scramble wall on the pillar in the middle.
Work your way along the wall, turn around, and jump to a diagonally facing wall into the room shown below. Jump into the next room with some ammo and an armor helmet on the ground. Press the skull button and head through the unlocked gate next to it. Jump to the next pillar and scramble around its walls to the right. Once you stop at a dead end, climb up and grab the code. This cheat kills any demon with a single hit from attack as long as they’re staggered.
The Infinite Ammo Cheat Code is found right at the end of the level. Before you place the final keys into the Gore Nest, jump back to the destroyed building. Look on the left side, as if you’re facing the Gore Nest, for a breakable wall.
Jump across to it and break it as you get there. Head inside and follow the path to the cheat code.
You can find the IDKFA Cheat Code in the ARC Complex. Head into the laundromat room where you’ll fight some demons. The cheat code is found in a small hole in the floor in the center of the room. This unlocks all fully mastered weapons and all equipment.
The Onslaught Cheat Code is easily missable. After you’ve been fired into a building by the artillery gun, clear out the room and then head right down the stairs.
Jump up into another room using the Grav Lift and grab the question mark to your right. This cheat activates Onslaught mode for the entire mission it’s selected.
There’s no Cheat Code on Sentinel Prime, so the next one is available to collect on Taras Nabad. The Overdrive Cheat Code is found after a small room demon battle. Head up the stairs in the image below and turn left.
You’ll see a wall you can break. Smash it and follow the path around. The Cheat Code is inside a small room alongside the mission’s second Secret Encounter.
The Famine Mode Cheat Code is located in the first half of the Nekravol level. In the room after you fight another Marauder, look to the cages of corpses being taken up by a chain pulley system.
Drop down when you see a break in the cages. Look above you for a ledge you can climb up. Head up there into a small room. You’ll find the secret alongside a Crucible replenishment item.
This Cheat Code stops demons dropping health or armor after death.
Suit Upgrade Gift
There’s one final Cheat Code you can get. If you fully upgrade your Praetor Suit in the ‘Suits’ section of the menu, you’ll be rewarded with the QuakeCon Mode Cheat Code. When this is activated, you’ll hear a crowd of people laugh and cheer as you rip and tear through each demon.
Link Source: Click Here