Finding a hidden level is a bit like discovering a wonderful landmark off the beaten path, or finding out that there’s another layer of biscuits in the tin at Christmas time if you’re a foodie. It’s a pleasant surprise and gives the player an immense satisfaction as they play through and explore an area that they may never have discovered had it not been for their perseverance as a gamer.

Or, it could just be happenstance: accidentally drifting off into a previously unseen location or a random button selection which reveals the otherwise un-revealed. In fairness, these can be equally as satisfying and certainly just as surprising as the level makes itself known as if out of nowhere.

And then there are the bonus levels and modes; levels which are deliberately rewarded to the player after completing the game or unlocking a certain portion of it. And though these levels do not necessarily take us by surprise in the same way (in fact, many of us have simply come to expect bonuses and unlockables these days!), it's certainly a nice treat for seeing the game through to the end, while increasing its lifespan at the same time.

Coming in all shapes and sizes in all different types of games, these levels hold a special place in the hearts of those who’ve played them, whether its due to their quality or the sentimental feeling they get when they think about that first discovery.

25 The Club (Call Of Duty 4)

Via callofduty.wikia.com

Coming at the very end of the main campaign, this level rounds off the story in quite a cryptic fashion. After infiltrating an airplane (with no explanation how or why), the player finds himself in a shootout with a group of presumably Russian bad guys.

The protagonist is unnamed and his colleagues are too.

However, the tight walkways, sharp turns, bathroom ambushes, and sense of urgency due to the level's countdown timer means that, even without context, this is still a blast worth replaying!

24 Guy Savage (Metal Gear Solid 3: Snake Eater)

via metalgear.wikia.com

After a rigorous interrogation which leaves him worse for ware, Snake finds himself holed up in a cell trying to survive on rodents, all while attempting to heal up and plan a daring escape. Saving the game with movie-buff Para-Medic, she regales Snake of the film Dracula. If you turn off the game and load that save, it begins a hack-n-slash dream sequence where Snake, controlling the Devil May Cry-inspired Guy Savage, hacks at demons wielding a sword. Upon waking, he even chastises Para-medic for giving him the nightmare!

23 Another Dream (Wolfenstein II: New Order)

via gamespot.com

So, another nightmare sequence that arises from your character nodding in the game. This time, if you take a map in the recent first person shooter title Wolfenstein II: New Order, it begins a nightmare sequence. That being said, this is no ordinary dream, it is a nightmare which sees you thrust back into the world of Wolfenstein 3D, the classic FPS title which helped create and popularize the genre. A taste of the old school shooter for new fans, and a fond stroll down memory lane for veterans.

22 Triangle (Tony Hawk's Underground 2)

via youtube.com (Benedict Gameplays)

The Tony Hawk series is well known for its hidden levels and locations (more will appear later on… or will they?) and this level is no exception.

Inspired by the Bermuda Triangle conspiracy, this level incorporates many elements surrounding it.

Situated on a deserted island in the Caribbean, this secret level contains discoverables within it, including Aztec ruins, an alien base, and a hot, menacing location which could be construed as the underworld (with a half pipe). Maybe that’s where all those ships went…

21 Special Zone (Super Mario World)

via nintendo.co.uk

Super Mario World—the iconic million selling SNES staple—has more going on beneath the surface than may be initially clear. A 2D platformer with cheery music belies a lengthy adventure with an almost overwhelming number of secrets and unlockables. Special Zone is an example of this. A secret zone within a secret, players must first find the secret exit in the Forest of Illusions level, and then find this challenging batch of stages, hidden in the Star Road level. Extremely complex, and for the hardcore Mario faithful only.

20 Arcade (Call Of Duty: Black Ops II)

Via polygon.com

Nuketown is one of the most beloved maps in the Call of Duty series. A 1950s-inspired suburban American location, it actually turns out to be a test site for nuclear weapons, giving the time limit for these maps online extra precedence. In the map, if you hit all the mannequins with headshots from your weapon, then you are able to play a bunch of vintage arcade games on a television in one of the houses. A throwback to two golden ages!

19 Inside The Statue Of Happiness (Grand Theft Auto IV)

via wikihow.com

Lying somewhere in between a secret level and an Easter egg (something the GTA series is famous for), the Statue of Happiness—located, fittingly, on Happiness Island—is an odd monument.

The GTA universe’s answer to the Statue of Liberty, it looks like Apex Twin in a dress (so, just like Aphex Twin).

It’s an odd statue that most players just tend to ignore. However, if you manage to get inside the statue, there is an actual beating heart within it. Weird!

18 Jill’s Sandwich Shop (Dead Rising)

via vripmaster.com

A reference from one game which found its way into another here. In Dead Rising there is a shop called Jill’s Sandwich shop. For the uninitiated, this may just come across as an innocuous title for a fictional restaurant in a fictional game. However, for those of us who’ve played the first Resident Evil, we recognize the title as being lifted from a hilarious quote from Barry in that game. Upon saving Jill Valentine from being flattened like a pancake by a descending wall, he comments that she was “almost a Jill sandwich!”

17 Secret Cow Level (Diablo II)

Via polygon.com

We’ve always felt that cows were secretly vicious being with the capacity to take human life. They’re fooling no one with that docile front that they put on! Diablo II takes our wild conspiracy and proves it without question with their secret cow level. Originally put in the game as a way to satirize the growing rumour that you could click on some cows in the game and portal to a secret level, here they actually make it a reality, forcing you to fight increasingly difficult waves of bloodthirsty moo-ers!

16 The Princess’ Secret Slide (Super Mario 64)

Via super-mario-64-official.wikia.com

On his search for Princess Peach, keen and curious Mario gamers are able to locate… her slide. Hidden behind a window in a one-star level, it is essentially just just a fun detour with the player just plummeting down a big slide collecting coins and goodies.

This level continued the tradition of secret Mario levels and bonus reward stages for persistent gamers.

After all, who doesn’t love the idea of going down a big slide collecting potentially life-lengthening coins without goombas to worry about?

15 Upside Down Castle (Castlevania: Symphony Of The Night)

via youtube.com

Castlevania: Symphony Of The Night is one of the most iconic side scrolling video games ever made, which is significant as it came right at the end of the 2D era. Taking place in Dracula’s castle, if the player completes a laundry list of tasks, they can actually turn the castle on its head! Adding a totally new dimension to the same game and map, players can venture through the castle from a totally different perspective, making it seem totally new and fresh

14 Secret Warp Room (Crash Bandicoot 3: Warped)

via reddit.com

Like most platformer titles, the third title in the cheeky bandicoot’s series is a game with a surprising amount of replay value and depth. One of the challenges that players can embark on is the collection of relics, which are rewarded to you by completing a second run through of a level within a time limit. Collect at least five relics and you unlock a secret warp room. Thematically strange, the room itself pulls back the curtain on how enemies are literally assembly-line manufactured. And the levels are even weirder!

13 Coco Time Trial (Crash Bandicoot 3: Warped)

Via youtube.com (gamerjgb)

As we alluded to earlier on, Crash Bandicoot 3: Warped is more than a simple platformer. With an array of relics and gems to collect and bonus levels to complete, there is plenty here to keep you coming back.

That being said, there are even secret levels hidden within levels on this PS1 platformer.

Crashing into a sign in the Road Crash stage, you’re suddenly transported into a different level as Coco on a jet-ski. Different than her other water levels, the sky is at dusk, water looks like boiling lava and enemies are much, much tougher.

12 Celebrity Players (NBA Jam Tournament Edition)

Via emuparadise.me

NBA Jam was one of the staples of 1990s sports games, the arcade-y basketball sim made for a formidable single player challenge and an extremely entertaining multiplayer experience. Gamers relished the idea of playing as their favourite NBA stars, and what could be better than that? How about pitting Fresh Prince-era Will Smith against then U.S. leader Bill Clinton on the court? With over 40 extra characters available to unlock, players can literally play the game without using any (then) active players on the NBA roster.

11 Joker’s Funland Secret Room (Batman: Arkham City)

Via batman.wikia.com

The secret level in Batman: Arkham Asylum we talked about earlier showed not only hints at the map of this, its future sequel, but key story points also. The tradition continues here. Located in Joker’s Funland on the island, the dark knight must crack an extremely difficult code to enter a locked room in the park. When he does, he finds clues alluding to the plot of the next game also, with writings and items related to Scarecrow and his use of nerve toxins.

10 Minecraft Room (Borderlands 2)

Via steamcommunity.com

Another example of one game paying cheeky but respectful homage to another.

And here, it should be noted, is one game giving tribute to another, completely different one.

Following train tracks in the Caustic Caverns, the player will eventually come across the “Minecraft Room,” an area filled with Minecraft enemies in a likewise environment enemies. To help with the immersion, your slick assault rifle is transformed into a blocky, Lego-like toy gun! If nothing else, it adds a bit of cheers and comic relief!

9 A New Level Every Time (Super Mario Bros./Tennis)

via newretrowave.com

Ok, so this is a really crazy one! Known for their secret levels, turns out you can unlock more secret levels in Super Mario Bros… by playing another game! If you take out the cartridge from the NES without correctly turning it off (warning, retro-gaming hipsters, this can damage the console!) and insert a copy of Tennis, then put the Mario game back in, it will unlock a secret level. Even crazier, if you do this more than once, you will be plopped into a different level each time!

8 Rat Man Chambers (Portal 2)

Via nerdreactor.com

Doug Ratman escaped GLAdOS when she took over the Aperture Science Enrichment Centre, is a bit of an enigmatic character of whom not much is known. It is fitting, then, that his Chambers are located off the beaten track of the linear title. Upon accessing the game through some gravity-assisted launching of main character Chell, Ratman’s presence is still in this place. These include plenty of writings on the walls and, most disconcerting of all, being able to hear his mutterings in the corridors.

7 Cheers/Prost (Fallout 4)

Via usgamer.net

Ah, the local! The watering hole where you can drown your sorrow among other cheerful individuals.

The main setting in Fallout 4 is Boston, which is also the location of the hit 1980s sitcom Cheers.

In the game, there is a inconspicuous place which, if you look at it carefully, is a recreation of the place where everybody knows your name! Don’t expect Sam and Norm to stroll in for a drink, however, as like everyone else in the place, they’ve probably long since perished.

6 Area 51… 2 (Duke Nukem 3D)

Via mobygames.com

Crash Bandicoot is not the only one who has visited the secret governmental site harbouring extraterrestrial beings. Duke Nukem, the bodybuilding, weapon-toting mercenary, has ventured into its hallowed halls too (albeit in a different universe). In his game, though, he wants to track down and eliminate an alien queen in typical Duke fashion. In a game which has been accused of being one dimensional and devoid of any depth, this shakes up the feeling and the environments of the shooter.