secret levels, but sometimes these are a normal part of the game, reachable through normal progression or level selection. Not to be confused with Gimmick Level.
- The Secret Cow Level in Diablo II is a secret level with specific requirements to reach it, that clashes a bit with the moody setting of the game. While still dark and realistic looking (by graphical standards of the time), it consists of grasslands containing a massive army of bulls who speak by saying the word "moo" over and over again.
- And then topped in Diablo III with Whimsyshire. After going through the steps to unlock it, the player is teleported to a mystical land of dancing flowers, smiling clouds, and lots of rainbows. Also doubles as a Take That, Audience! after all the complaints that the early screen shots weren't dark enough.
- The secret "Out Of This Dimension" level in Star Fox. The enemies are origami paper airplanes, the background is constantly distorting planets with faces, and the boss is a slot machine. Unfortunately, coming here prevents you from progressing through the remainder of the game, as once you defeat the boss you are left with an endless "THE END" screen.
- Paper Mario: The Thousand-Year Door has you doing classic levels from Super Mario Bros. as Bowser at three points.
- Star Trek: Elite Force II had a secret level based on Super Mario Brothers.
- The Secret Level of Batman Doom. See its work page for a more detailed description.
- Wolfenstein 3D has a Secret Level with the layout of a Pac-Man stage called "Wolf Pack", complete with ghosts that chase you, as seen here.
- Night Sky: The vividly coloured "Slightly Nonsense", which is a stark, sunny contrast to the moody sunsets of the preceding worlds, and requires all of the secret stars to access.
- Portal 2 has a test chamber which has the word "TEST" written in enormous letters on a wall and is solved as easily as pushing a button. It's designed first to show that Wheatley has no idea how to design a decent test and also as a jab towards the kind of level uncreative users create when they first get their hands on a game's SDK.
- Abobo's Big Adventure has a level based on Urban Champion. The champ's attempts to hurt you are ineffective, and he's a total pushover. It ends with a sequence direct from Mortal Kombat (a game that wasn't on the NES).
- AS-Outback, an assault mission from Unreal Tournament 2004, is one long parody of the Land Down Under, wherein pissed-off Aussie rednecks, infuriated by the alcohol-free zero beer, go to their local brewery to get back some real beer, fighting against the city slickers who prefer the nasty stuff.
- Naruto Shippuden: Ultimate Ninja Storm Generations has The Tale of Killer Bee, which consists of 4 fights with absolutely zero plot justification, sandwiched between Killer Bee rapping about how awesome he is and who he's going to fight next. It certainly fits the "clashing with the overall mood of the game" part of the description. Beware of the surprise SNK Boss at the end though!
- Super Meat Boy has worlds which get progressively darker in tonenote . When you finally finish the game, you unlock the Cotton Alley, which is bright, pink, and full of cheery music and things trying to murder you horribly.
- Doom II has the secret Wolfenstein 3D levels. (Apart from the German version, which omitted them, for obvious reasons)
- TNT: Evilution's secret levels take place in a pyramid and the Caribbean.
- Frog Fractions has a level where you're back at the pond at the beginning of the game. You are now a human, and obviously you no longer have the Overly Long Tongue that's central to the gameplay. You inevitably lose, but thankfully it was All Just a Dream.
- The multiplayer map of the first Dungeon Siege game has a secret chicken level in which the player has to fight giant chickens, named after employees of Gas Powered Games. Defeating the final boss of the level gives the player a gun...that shoots chickens. To enter the secret level, the player has to possess 3 fairly hard to find, but useless items.
- Sound Voltex has "Nyan Cat".