For those fans who wish to know how it's possible to unlock classic DOOM levels in id Software's fast-paced first-person shooter, follow along with our guide.

Ever since Bethesda's and id Software's DOOM reboot officially released, fans of the gory FPS have been tearing through the game and have gone on to find loads of interesting secrets. For starters, one eagle-eyed gamer spotted an Elder Scrolls 5: Skyrim Easter egg that alludes to the final resting place of the fantasy-RPG's protagonist the Last Dragon-Born, while lots more players have undoubtedly discovered the fun little reference to the popular action film Terminator 2.

Perhaps the most appealing hidden goodie of them all, however, is the game's ability to allow fans to take on some of id Software's original DOOM levels from the very first iteration of the title. Players who have never experienced the thrill of playing what many consider to be the granddaddy of first-person shooters would do well to read on below so as to find out how to unlock classic stages from the franchise.

Every mission within DOOM contains this secret, so the best example for fans to use while scouring for the concealed locations is the instance found early on in the game's single-player campaign, where players will eventually find themselves in the game's Foundry level. Within it, there's the potential to access the E1M2: Nuclear Plant stage from the earliest incarnation of DOOM in 1993 complete with the original textures, music, pickups, as well as collectibles, and in order to do so, gamers must be on the lookout for a grounded lever that will open a door nearby which almost appears to be a hidden panel.

Bearing this in mind, in the Foundry, fans ought to come across the switch in the main entrance hall on a platform branching off the side of a catwalk that rests high above the base level's gigantic pit of molten lava. More specifically, fans will find a the mouth of a slow-moving lava waterfall close to the spot. After jumping over the walkway's guard railing and activating the lever, a portion of the wall up ahead will slide away to reveal the entry point to the original DOOM's E1M2: Nuclear Plant.

As will be the case with all of the classic level Easter eggs in DOOM, once each of the carefully secluded secrets become activated, the full versions of the maps will be unlocked in the game's main menu since the solo-mode only contains fragmented versions of the stages. With this being the case, id Software's decision to essentially include a DOOM game within itself is certainly just one more reason for many to ponder why it could be the best shooter of 2016.

Did you find our primer to finding DOOM's classic level Easter eggs helpful? Have you found them all yet? Let us know your thoughts in the comments below.

DOOM is out now and is available for PC, PlayStation 4, and Xbox One.