Every video game contains hidden secrets and Easter eggs. As a player, finding them is never a small feat. Even if they are easy to spot, it always feels like you've discovered something special that you were never intended to see.

Sometimes developers put these secrets in places that are hard to reach, but most Easter eggs are found pretty quickly — especially nowadays, when the ins-and-outs of every video game can be learned with a quick internet search. These secrets, though? These are some of the rarest, most well-hidden secrets in the history of video games.

It has taken gamers decades to find some of these treasures. Not only are these Easter eggs super obscure, but many of them were never meant to be found by the player. Whether it's a well-hidden reference, a secret item, a shocking glitch, or a newly-explorable area, these hidden gems were so hard to find that some developers thought that they would never be seen by anyone! Have no fear, completists, because we're here to help.

For this list, we've collected some of the most obscure long-standing video game secrets in the entire world. The list spans generations in technology, and sometimes the secrets are so complex that they lead outside of the game world itself. Seriously, some of these are so crazy that you'll wonder how anybody ever thought to look for them in the first place.

Think you've found them all? Here are 20 Hidden Things In Video Games That Weren't Found For Years.

Quincy Sharp's Office (Batman: Arkham Asylum)

Arkham Asylum is chock-full of Easter eggs and references. If you're a DC comics fan or a Batman aficionado, these can be quite easy to catch. However, this one is so hard to find that players may never have never found it had the development studio not leaked its existence nearly three years later.

In Warden Sharp's office, there's an unmarked wall.

It's totally inconspicuous and Batman's detective vision (which usually lets the player see through breakable walls) will register it as any other ordinary wall. However, detonating explosives on the wall will unveil a hidden room. In this room is a number of references to Arkham Asylum's sequel, Arkham City.

Rocksteady Studios teased Arkham City years before its release. Because nobody found the room, nobody noticed.

Happy Birthday Lauren! (Halo 3)

Master Chief in Halo 3 trailer

The Halo series is infamous for its collectable secret skulls that unlock gameplay modifiers, but this secret was a little bit different. Bungie coder Adrien Perez wanted to leave a message for his wife Lauren in his company's newest project.

Starting a single-player level in Halo 3 and holding down the thumbsticks will reveal "Happy Birthday Lauren!" in the loading screen's ring. How sweet! This can only be seen on December 25th of any given year, so either break out your copy of Halo 3 next Christmas or set your console's date and time accordingly.

It's a cute little Easter egg that went unnoticed for many years, but let's hope that Lauren really was the first person to discover it!

Splinter Seals (Splinter Cell: Double Agent)

Tom Clancy's Splinter Cell games are known for their gritty military action, so players were pretty shocked when they stumbled upon a secret set of quests involving space-travelling seals wearing party hats.

Throughout the game, the player must collect a variety of items for the seals. 

They reward the player with information about the next seal's location, as rescuing them all will return them to their home. Rinse and repeat until you've found them all, and their princess will express her gratitude.

Splinter Cell: Double Agent is an especially dark entry in the franchise too, as Sam Fisher has to go undercover in a terrorist organization in order to shut them down. A noble endeavor — perhaps just as noble as getting Muffin, Cookie, Vanilla, Buddy, and Pepperoni back to their home planet.

Zelda Chris Houlihan Room

If you ever stumbled upon this odd treasure room in A Link to the Past, you were probably momentarily confused before you were overwhelmed with joy.

The Chris Houlihan Room is a "secret" location named after the winner of a Nintendo Power magazine contest, with the prize being the winner's name featured in a future Nintendo release.

The room appears during a glitch — when the game doesn't know where to spawn Link, it defaults his position to this room. There are several ways of triggering the glitch, but each will end up in Chris Houlihan's rupee stash.

Unfortunately for Mr. Houlihan, his name only appears in the original game, as the text is replaced in the Game Boy Advance version.

The Man In The Green Jacket (Resident Evil 4)

Leon S. Kennedy holding a handgun while zombies stalk him in Resident Evil 4.

This might be one of the spookiest things in Resident Evil 4 and it took over 12 years to find.

Right after the helicopter crash sequence, a mysterious figure can be seen in the background out of the game's playable area. The game's color grade is so dark and dim that it is nearly impossible to make him out, but freeing the camera enables for a closeup that still doesn't explain much.

Way off in the distance is a blurry, 2D figure of a man in a green jacket.

He's smiling and holding up peace signs (we think), and there's really no reason why he should be standing here. This is likely the developers playing some kind of inside joke, but the man remains a mystery.

The Impossible Coin (Super Mario 64)

It's common practice among video game completists to prefer platforming games littered with collectables. Progress can easily be tracked along the way as they grab each item, so it's always clear how far any given player is from completing the game with a 100 percent rating. However, Super Mario 64 has a coin that nobody has ever collected — without cheating, of course.

This slope of coins on Tiny Huge Island is supposed to be a row of five, not four. Because of a small programming mishap, the fifth coin that should appear at top of the slope actually spawns underground, thus making it completely inaccessible.

This hidden coin has made players grit their teeth for decades. It's so close we can taste it!

Beating The End (Metal Gear Solid 3: Snake Eater)

Solid Snake has dealt with some tough enemy encounters, but none of them are as tough as The End-- or as easy, if you're aware of this secret.

The End is a veteran sniper and one of the game's hardest bosses.  The battle might last a while, but players who took a break from the game for over a year were gifted with an odd surprise.

Waiting at least a year to finish the boss battle will result in nature taking its course. The End's old age will catch up with him.

Snake won't have to lift a finger.

Fast-forwarding the console's system date one year yields the same result, if you're in a hurry. Careful, though, as shorter breaks from the game may result in Snake getting captured by enemy forces.

The Sarcastic Announcer (Wave Race: Blue Coast)

This jet ski racing title on the Nintendo Gamecube has an Easter egg that took 10 years to find. Was it worth it? Probably not — unless you really like getting passive-aggressively insulted about the way you play Wave Race.

Going to the game's options menu and inputting a secret code makes a very bizarre change to the in-game narrator. Using the code and starting a race will reveal that the upbeat announcer is suddenly feeling a lot more grouchy and sarcastic. His words of encouragement suddenly turn into dry quips and insults, and his voice becomes bored and monotone.

You'll suddenly feel a lot more insecure about playing a breezy racing game, but it's a cool secret nonetheless.

Big Foot VS. Teen Wolf (Grand Theft Auto V)

A few years ago, Grand Theft Auto V players found mysterious peyote plants scattered across Los Santos that would turn avatars into a Sasquatch when collected. Yes, really.

This seemed like the Easter egg at first, but it led to something much weirder. As dedicated community of players combed through the game's code, they realized that the plants were leading them somewhere.

It turned out to be more of a literal hunt than a scavenger hunt, as eventually players stumbled upon the Beast, a Michael J. Fox-looking werewolf that attacks on sight.

Beating the Beast rewards the player with his Teen Wolf inspired costume. Seriously, what else could possibly be hidden in this game?

Calendar Man's Monologue

Arkham Asylum teased the events of Arkham City, but Arkham City managed to one-up its predecessor with an even more cryptic secret. Visiting Calendar Man on different days will result in different conversations between him and Batman. However, setting your console's date to December 13, 2004 will reveal new dialogue.

Calendar Man will reference the end of the following game, Arkham Knight, and promise Batman that he'll be present for his demise. The ending of Arkham Knight does indeed feature Calendar Man, and the date corresponds to the founding of the game's development studio, Rocksteady.

This secret was only discovered three years after release when a mysterious video appeared online by uploader "JG Jour" — a french twist on Calendar Man's identity, Julian Gregory Day. Did Rocksteady leak this secret too?

Hangar 96 (Marathon Infinity)

This classic first-person shooter has had quite the reputation over the years, but even the most experienced Marathon players might not know about Hangar 96 — the game's secret multiplayer map that, essentially, players must program into the game themselves.

Marathon Infinity's three bonus levels all refer to a mysterious arena that the player never encounters.

At first it only seemed like a story element and not a playable location. However, two computer terminals can be found in the first and last levels of the game that contains tons of hexadecimal code.

Running that hex code through several programs (we're putting it really simply, here) will piece the level together and unlock it for your enjoyment. It's extremely complex unless you happen to be very tech-savvy, but Hangar 96 was secretly there all along.

Playing As Master Hand (Super Smash Bros. Melee)

Back in the day, it was easy for your friends to lie and tell you about all the secret characters they unlocked in 2001's Super Smash Bros Melee. The cast was so large that anything seemed possible, but little did anybody know that playing as the Master Hand boss wasn't just a myth.

Master Hand is playable in versus mode thanks to the "Name Entry Glitch", which has been perfected by Smash enthusiasts.

The step-by-step guide can be found here, though it mainly involves tricking the game to advance past the character select screen without actually choosing a character.

Triggering this glitch might take practice, but it'll be worth it when you blow your friends' minds by doing what they thought was impossible all those years ago.

The Island (GoldenEye 007)

This gaming myth has plagued GoldenEye fans for years and they might be upset that it did. James Bond must infiltrate a Byelomorye Dam in the game's first level, but players may be distracted by a distant island across the water. Many believed it to be a secret area that must be unlocked, or an Easter egg that nobody truly knew how to activate.

The secret island went on as fiction for many years until the age of the internet, where players using cheats would document the location once and for all. It turns out that the island is just an unused section of the level that was never fully modeled or programmed. How disappointing!

At least now you can call out all your friends who lied to you about "unlocking" the secret island.

The EJB Menu (Mortal Kombat I, II, And 3 Arcade Cabinets)

Johnny Cage in Mortal Kombat 1

Back in 2016, secret menus were discovered hidden within the arcade cabinets of the first three Mortal Kombat games that allow for some pretty mind-blowing stuff.

A precise combination of button-presses unlocks a secret menu for Ed Boon himself, the series' co-creator.

The menu consists of some diagnostic options, a list of credits, and even character endings that can be viewed without completing the game. Mortal Kombat 3's menu even enables the game's locked characters and allows access to a Galaga-esque mini-game.

This secret took so long to find despite Mortal Kombat's immense popularity. It just makes us wonder what else is hidden in the arcade classics that we didn't have time to explore as kids.

Saving Anytime, Anywhere (Silent Hill 2)

Silent Hill 2

Silent Hill can be quite the stressful experience, but what if we told you that you could play the game with a map and save your progress any time you wanted?

Despite the fact that the game is 17 years old, two new features were recently discovered that make the horror game a whole lot easier — after you've completed it. Players who managed to receive the secret "Dog Ending" must have their controller set to "2" and start a new game.

This will unlock button combinations that enable a mini-map to display your surroundings.It also renders the save checkpoints useless by adding a save-on-demand feature. This might lessen the challenge a little bit, but hardcore fans may want to give this a shot anyway.

Another Rainbow Coin (Donkey Kong 64)

Video game completists might want to find something to bite down on. Are you a fan of Donkey Kong 64? Have you collected everything? Sorry, but no. You likely haven't.

Players have found a previously unrecorded Rainbow coin in the level Fungi Forest, simply hiding in a patch of grass.

The game's former 976 coin-count has now been raised, and any players who thought they had collected every item may not feel as successful as they once did.

This coin isn't necessary for completing the game at all, but still — it has seemingly evaded players all these years, just like the coin in Super Mario 64. Who knows what else fans have missed!

Watch The Crowd

Mike Tyson Punch-Out - Best Video Game Bosses

One-hit knockouts have never been a big secret when it comes to Mike Tyson's Punch-Out. However, if you really want to impress your friends, certain fights use visual cues that tell you precisely when to throw that winning punch.

During fights with Bald Bull, a man in the top-right corner of the screen lets the player know when to knock him out. Look closely — he's sitting in the front row, holding a camera.

When his camera flashes, it means Bull is vulnerable for that finishing hit. Similarly, fights with Piston Honda utilize the bearded onlooker in the top-left. He'll duck when it's time to punch.

These small cues somehow went unnoticed for 30 years! If somebody had noticed them, they should have spoken up years ago and saved us all that frustration.

The 30-Year Cypher (Gumball)

This long-lost Apple II game has been forgotten even by veterans of the video game industry, but when game preservationists known as "4a.m." and "qkumba" began to archive it online, they stumbled upon some odd lines of code.

Investigative work led to a discovery — secret codes and cyphers hidden throughout each level.

After playing through Gumball and solving all the codes, this screen appeared. It was a congratulatory message from programmer Robert A. Cooke, who was shocked to hear of its discovery.

4a.m. tweeted at Cooke upon his success, to which Cooke responded with "WELL DONE. I assumed it would take a thousand, but you solved it in a mere 33 years."

The message also suggests that a second set of cyphers exists in another game that Cooke worked on. Time to get cracking, guys!

The Mystery Box Of 2113 (Trials Evolution)

You wouldn't expect it from a quick glance, but motorcycle racing game Trials Evolution sends eagle-eyed players on one of the greatest Easter egg scavenger hunts -- maybe ever.

Following the trail leads to spectral analysis of a secret song, deciphering Morse code, and literally scouring the globe for boxes of keys buried underground. It's extremely complex and hard to follow, but clever hunters have learned quite a bit about the mystery.

The best part? The secret still hasn't been completely uncovered. The most recent clue shows that one of the buried keys will open up a box that will appear underneath the Eiffel Tower in the year 2113 — a video game secret that will literally stay hidden for a lifetime.

A Literal Easter Egg (Grand Theft Auto: Vice City)

Leave it to Grand Theft Auto to give players an actual Easter egg. Could things be any more meta?

The VCN building on the northern end of the city sits adjacent to a smaller building with a helipad on top. Jumping from the helipad through the VCN building's nearest window will lead players into this room. Have no fear — the window is a flat texture that looks like an ordinary wall, but Tommy will phase through it and land safely.

Inside the room is a chocolate egg on a pedestal, making this quite literally a video game Easter egg. 

Vice City Stories also features this secret, though the egg will be under construction beside a miniature crane, as that game is a prequel. How adorable!

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Did you miss any of these long-hidden secrets? Leave a comment before you go and tell us which ones you found!