Completionists who took on Doom Eternal can't help but laugh when someone claims that the game only takes about thirteen hours to beat. Maybe that's how long it takes to complete the story. However, conquering every aspect of the game takes easily double that time for curious minds who aren't satisfied until that 100% completion achievement pops up on the screen.

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Does The Ancient Gods Part One reward or punish gamers that can't rest until every last stone has been unturned? Much like the gameplay of the core game, the DLC makes a statement that the reward and the punishment irrevokably intertwined. If it were easy, then it would be less satisfying. This list hopes to assist players in finding the secrets located in the most obscure areas.

10 Sinking Into The Swamp

Doom Eternal The Ancient Gods Part One Secret By Wall

The issue with The Blood Swamp is that it's hard to tell what is dry land and what is a puddle. Some puddles are radioactive or submerge players underwater, so there is a negative incentive to go around stepping in them.

Yes, stepping in every puddle is going to make the game even harder on players, but this secret can't be found without it. The puddle is almost impossible to see and it's next to a wall that players have no reason to approach (pictured). If that's not hard enough, this Codex is protected by its very own mob.

9 Jump Dash Punch Dash

Doom Eternal The Ancient Gods Part One Breakable Wall

Some secrets in the game are hidden so well that everyone misses them the first time around. But that's not the only way areas are made impossible to get to. Doom Eternal also loves to torment completionists by hiding secrets in plain sight.

The Blood Swamps does a bit of both for this secret. Players have to make a trust fall off a cliff going the wrong way and then they get to this obstacle; a punchable wall with a lethal cliff in front of it. Players have to perfectly execute a jump, dash, punch, dash combo, or else die and try again. After some more puzzle-solving with a punch block, the secret area accesses a Secret Encounter.

8 Two For One

Doom Eternal The Ancient Gods Part One Wall Platform

Thought the days of making ridiculous platform jumps were behind the Slayer? Think again. This final codex in The Blood Swamps requires jumping in the wrong direction first, usually after players die when approaching it head-on. This one has been making players miss the days when Marauders were the hardest thing about the game.

By the final castle, several floating spires make up a bunch on lily pads for the Doomguy to do his best frog impression on. At first, they get close to a climbing wall with some armor on top, but not close enough. Players have to follow the spires around the back and up a jump pad, then loop around. After finding this armor, the codex is an easy jump and dash across the way.

7 One Chance

Doom Eternal The Ancient Gods Part One Turbine Jump

As if trying to beat the game on ultra-nightmare isn't hard enough, The Ancient Gods Part One makes this secret so hard to get that if players who get the platforming right can't get it until the next playthrough. That's not a typo, players need to get this jump wrong or else restart from an earlier point.

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Partway through the UAC Atlantica Facility, players will have to shoot a turbine to make it spin, then jump into the current and get blown over the ocean. A handy climbing wall awaits them, but those who want the codex entry will actually have to miss the jump and go wide to the right at the last moment, then dash perfectly to grab onto a ledge with a codex.

6 Platforming Under Fire

Doom Eternal The Ancient Gods Part One Slayer Key Start

Inside of the rig at the UAC Atlantica Facility, there is an opportunity to get a key so long as the player has a death wish and doesn't mind getting shot at in midair by one of The Ancient Gods Part One's new enemies.

Players have to look over the side of the railing after climbing some boxes to notice a distant swing pipe. Even after grabbing that, the Slayer will have to ignore every pro advice given in Doom Eternal and keep swinging toward the incoming fire. On the right, an air duct will lead to the Slayer Key.

5 Diving In

Doom Eternal The Ancient Gods Part One Oxygen by Secret

All of those instincts that kept players alive for nightmare mode need to go out the window. Inside of the oil rig towards the end of the map at the UAC Atlantica Facility, The Slayer will have to jump into the water on a total whim.

A little swimming around yields an oxygen tank, which lets the player know that this is not the small, encased room it appears to be. Taking a right when facing the tank for a short swim which ends at a jump pad. Hopping on it leads to another Secret Encounter.

4 Cliff Diving

Doom Eternal The Ancient Gods Part One The Holt Cliff Codex

Any game that claims to be a harder FPS than Doom Eternal might need to re-evaluate with the debut of The Ancient Gods Part One. Not only is the combat on a different tier entirely, but blind jumps have become standard fare.

Sense a reoccurring theme here? Again, players that want this Codex entry in the early part of The Holt will find it after punching down a tree. Instead of continuing straight ahead, players will have to jump off the cliff (pictured) and hug the wall to land on a nearly-impossible-to-see outcropping.

3 Shooting The Ceiling

Doom Eternal The Ancient Gods Part One Ceiling Secret

At first, this one doesn't seem too hard, since the player passes right by a laser grid with an easily visible secret inside of The Holt. The exact reason why demons decided to put Secret Encounters right next to the Slayer is just another one of those nonsense Doom Eternal mysteries.

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Despite all of the downward motion on this list, the developers haven't forgotten to hide a thing or two on the ceiling as well. The button opens the door to progress, but it also silently moves a metal panel overhead. Shooting the button disables the grid.

2 Window Shopping

Doom Eternal The Ancient Gods Part One The Holt Slayer Key

Those who don't have their head in the clouds because they are dealing with some seriously horrifying creatures won't notice a Slayer Key on the cliffs to the right in The Holt. Spotting it is only half of the battle.

Players can try all manner of platforming skills to try and reach it, but it's of no use. This key can only be grabbed, ironically, after giving up and moving up the collapsed log to the next area. The cliff on the left can be scaled and doubling back nabs the elusive key.

1 The Road To The Slayer Gate

Doom Eternal The Ancient Gods Part One The Holt Slayer Gate Map

Usually, maps are used to lead players, but a crafty game designer can sometimes use them to mislead them as well. The Slayer Gate gives off a nice purple hue on the map that doesn't seem hard to get to, but it does appear to be in the opposite direction of a Secret Encounter and an Extra Life.

Collect these and then head toward it. The Slayer Key from the previous section unlocks the second gate, but most players give up too early when another inexplicable gate blocks the path. This one is only opened after defeating the nearby enemies.

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