Secrets are part of Doom's DNA. Ever since the first entry in the franchise, perceptive players could get a leg up by exploring levels to find hidden weapons and fun collectible items.

RELATED: 10 Hidden Plotlines Everyone Missed In Doom Eternal

Doom Eternal continues this trend, going so far as to add a hub area—The Fortress of Doom—that displays your collection of toys and music. While this game's secrets are much easier to find this time around, there are still a few that elude most players. Whether it is a hidden toy or a tribute to a classic title, here are Doom Eternal's 10 best secrets you likely missed.

10 Zombie Earth Toy

The first level of Doom Eternal throws the player straight into the action just as Doom 2016 did. Blasting Zombies with a Combat Shotgun never gets old.

During that introduction, players might have missed the game's first toy collectible. As you leave the room that provides the Chainsaw, there is a vulnerable wall in the corner of the room. Punch it and follow the path to obtain the Zombie Earth Toy, the first toy in Doom Eternal.

9 Silver Bullet Cheat Code

Via: Video Games Source

If you loved the Golden Gun in Goldeneye 007, Silver Bullet turns every gun into a one-hit kill when the enemy is staggered. To obtain this cheat code, you will need to explore the Doom Hunter Base level.

RELATED: Doom Eternal: 10 Best Weapon Upgrades

As you play through the level, you will come across a circular room with a large pillar overlooking it in the center. You will have to climb up the room to progress, but the game will guide you to one end of the room. Instead, turn around and jump on top of the large pillar to receive this sneaky cheat code.

8 Dopefish

Cultist Base is one of Doom Eternal's best levels, featuring a beautiful landscape to fight demons in, fast-paced encounters, and a level packed with secrets.

A few secrets in this level feature this strange-looking fish. Fans of the Commander Keen series will recognize this as Dopefish, the second dumbest creature in the world. It looks much stranger than the Commander Keen counterpart, having bloodshot eyes and yellow teeth. Blowing these guys up will typically reveal a hidden extra life or similar secret.

7 Slay Cancer

In Super Gore Nest, players head back to Earth to fight the forces of Hell protecting a city infested with demonic flesh. Many secrets fill this level, but none are as impactful as this easter egg.

During the first arena, head to one of the shops at the top left of the arena. Looking through the windows will reveal a top hat with a plaque that reads "slay cancer." This is a reference to the revered YouTuber TotalBiscuit, a games critic that was mostly known for his first impression on video games and e-sports shoutcasting. He was a fan of Doom 2016 and tragically died of cancer in 2018. It doesn't count as a collectible, but this tribute is worth seeing yourself.

6 Taras Nabad Sentinel Battery

Sentinel Batteries are items that can unlock rewards in the Fortress of Doom, including Weapon Mods and new skins. You typically earn them by completing level challenges, but they can also be found as secrets.

Taras Nabad contains a couple of Sentinel Batteries. The trickiest one to obtain is the second Sentinel Battery. After slaying your first Arch-vile, look for a Night Sentinel statue at the top-right of the arena. Punch it and it will reveal a button. From there, you will need to punch a chain to reveal this hidden item.

5 Quake 2 Rage Music

Via: Rookie425 (Twitter)

Yet another secret in Taras Nabad, players can find Quake 2's Rage music track later in the level. This collectible isn't just visual, either. You can play these tracks in their entirety in the Fortress of Doom.

When you arrive at the circular room that asks you to punch a hanging weight down, look at the top of the circular room for a crack in the wall. It should be right above where you entered. Activate the gravity lift and dash towards the weakened wall. Punch it and you'll find this classic Quake 2 track.

4 Cultist Base Slayer Key

No arena encourages you to rip and tear more than Slayer Gates, optional challenges that require mastery of the game's mechanics. Completing all six of them rewards the powerful Unmaykr weapon, but some of these Slayer Keys are tricky to find.

On Cultist Base, players will stumble across a room with a massive cyberdemon decoration they must punch down to proceed. That room also contains a Slayer Gate, but the key seems inaccessible. To get the key, you'll need to climb on the wall at the end of the room to your left. Instead of climbing up like normal, head downward and dash through a dimly-lit opening. It will lead to the Slayer Key and allow you to open the Slayer Gate.

3 Fortress of Doom Suit Cheat

Via: ZaFrostPet (YouTube)

To unlock every suit upgrade in Doom Eternal, you can either obtain all Tokens from Night Sentinel spirits or find the Fully Upgraded Suit cheat code.

RELATED: 10 Tips To Make An Overpowered Doomslayer In Doom Eternal

Towards the end of the game, Samuel Hayden will tell you that this is your last chance to explore the Fortress of Doom before the game's final levels. During this time, head to the room that The Crucible resides in. Look for a red button on the top of the room and hit it to activate a jump pad. Launch yourself upward to obtain this secret.

2 Nekravol Baron of Hell Toy

Have you collected every toy except the Baron of Hell? If so, you might also be wondering how to find your way into this hard to reach area in Nekravol's opening arena.

Monkey bars will guide you to a specific tower overlooking part of the area. Hop on them and look for a climbable wall to your left. From there, jump off to your left and you should be able to land inside the structure and obtain an extra life. Under that life is the Baron of Hell toy.

1 Urdak Secret Encounter 2

Out of every secret in Doom Eternal, Urdak's second secret encounter is easily the game's most hidden area. The challenge itself is easy, but finding the Gore Nest to start it requires a sharp eye.

Around halfway through Urdak, players will have to swing across two monkey bars to reach an interactable door panel. Before you head into that room, look to your left and you should see a weak wall. It is right after the second monkey bar you swing from. Dash into it and you'll find both an extra life and the level's second secret encounter.

NEXT: Doom Eternal: 10 Tips To Survive Nightmare Difficulty