Stumbling upon Easter eggs in video games is always fun for eagle-eyed players, and developer id Software's latest in the Doom series certainly does not disappoint. The recently-released first-person shooter is peppered with cool nods to past games, movie references and even demonic symbols.
In our glowing review, we said of the game: "Intelligent, fresh and endlessly enjoyable, Doom is more than a tribute to its beloved progenitor. Taken in its own right, this is the most finely crafted, technically impressive pure shooter in over a decade."
Since the game's release on 13 May, discerning gamers have spotted quite a few entertaining Easter eggs while exploring the passageways of the Mars base and the dark depths of Hell. When you're not busy eviscerating demons and other monstrous entities, here are some of the best hidden goodies to go back and discover for yourself.
Remember the line repeated by the guards of The Elder Scrolls 5: Skyrim – "I used to be an adventurer like you, but then I took an arrow to the knee" – you probably remember it becoming an annoying meme through late 2011 and early 2012.
Well, while exploring the dark caves of Hell, gamers can find a corpse wearing Skyrim's familiar horned Dragonborn helmet, and of course there's an arrow in its knee – a clear nod to the RPG developed by Doom's publisher Bethesda.
2. Terminator 2: Judgment Day
This cool tribute to James Cameron's Terminator 2: Judgment Day from 1992 is triggered when you drop your playable character into the scorching hot lava of an early level set in a foundry.
As protagonist Doomguy (a loving fan-name) dies, he re-enacts the end scene from the movie, in which Arnold Schwarzenegger's time-travelling android killer is terminated. As Doomguy sinks into the molten pool, he flashes the same memorable thumbs-up.
3. Fallout Vault-Tec
In the Fallout universe (another of Bethesda's RPGs), the Vault-Tec Corporation built underground vaults to protect people from the nuclear apocalypse. Except, they weren't there to just protect people, they actually served as giant testing labs examining how people would respond to different environmental conditions.
One reference to Bethesda's popular franchise can be found on the bottom of one of the vault-like doors on Mars, which has the words "Area Lockdown" on it. Below it, players can find a sticker featuring the Vault-Tec logo.
4. Commander Keen
Another interesting, not to mention sinister, Easter egg found in the new Doom is this reference to id's classic, side-scrolling game Commander Keen from the early 1990s. The game featured an eight-year-old adventurer called Billy Blaze who travels through space under the secret identity of Commander Keen.
Blaze's iconic yellow helmet can be found inside a hidden cave while playing the 6th mission "Kadingir Sanctum." However, it is now worn by a skull propped up on a stick, presumably after Blaze died a brutal death. It is also a reference to an earlier Easter egg in Doom 2, in which four sprites of the little guy were found hanging from a ceiling at the end of level 32.
5. Doom 3's Soul Cube weapon
In Doom 3, the powerful Soul Cube, powered by killing enemies and absorbing their souls, was the only weapon capable of destroying "Hell's mightiest warrior" – the Cyberdemon.
The artefact can be found in the game's ninth level, Lazarus Labs. Unfortunately, players can't interact with it or use it in the reboot.
6. Bejeweled-type mini game
Players exploring Lazarus Labs will also come across a dusty computer in a lab that activates a playable Bejeweled-type mini-game called Demon Destruction.
Rather than matching pretty gems, players must match enemies and explosive barrels from the original Doom.
7. Doom 3's Super Turbo Turkey Puncher
In the 8th mission, "Advanced Research Complex," players can find an old arcade machine hidden behind some crates where gamers can play Super Turbo Turkey Puncher, the mini-game from Doom 3 that allows you to punch turkeys for as long as you like.
8. Quake and Original Doom posters
Gamers can find another Easter egg hidden in the Advanced Research Complex in a secret room towards the beginning of the 8th mission.
To find this hidden nugget, make your way to the women's restroom, climb up the vent and follow the tiny tunnel to a room on the other side. On one blood-spattered wall, you will find two posters referencing the Quake franchise and the box art for the classic 1993 Doom.
You can also find another Quake logo inside one of the lockers as well.
9. Classic Doom levels
Prior to the latest title's release, id Software revealed that players can find slices of the original Doom hidden in each of the game's single-player levels.
To trigger these Easter eggs, players need to find a hidden lever that, once activated, will play a jingle and open a secret door leading to a section from the classic Doom and its sequel.
Varying in size, these nostalgia-laden sections sport the same graphics style and, in some cases, music from the original maps. However, players can still use weapons from the Doom reboot to take on enemies.
10. Happy Birthday Easter egg
In the 10th level of the new Doom, Titan's Realm, players can find another random, but fun Easter egg hidden away.
Within the mission, you will find a ledge sticking out of the wall with a gap that seems too small for a Marine to enter. However, jumping onto the ledge will lead you inside a hidden tunnel where you will find a secret, grim birthday party, complete with a skeleton wearing a party hat, a "Happy Birthday" balloon and a cake beside him.
11. Pentagrams and '666'
Developers clearly left no stone unturned when it came to planting cool hidden references and details in the reboot.
Reddit user TomButcher recently found that Cyberdemon, one of the songs in the Doom soundtrack, actually contains the "number of the beast" – 666 – and hidden pentagrams when its frequencies are visualised through a spectrogram.
12. Doom 2's Icon of Sin
A much less powerful version of the final boss from Doom 2, the infamous Icon of Sin, is seen in the reboot's 11th level, The Necropolis.
While you can't fire at the boss to destroy a hidden severed head of John Romero in this edition, it will chuck a projectile containing a cute mini-space marine doll, if you shoot it in the right spot.
13. Sean Bean is dead (again)
No matter who he plays, Sean Bean's characters always seem to die in almost every TV show and movie he stars in.
Even though he is not associated with the game whatsoever, Doom's developers decided to include this little fun fact in the reboot as well. According to a tweet from Richard Cobbett, Doom players can find a screen that shows the names of more than 61,000 people who have died on the base. Hilariously, Sean Bean's name is also featured among the listed casualties.