Spelunky is a 2008 source-available 2D platform game created by independent developer Derek Yu and released as freeware for Microsoft Windows.

The player controls a spelunker who explores a series of caves while collecting treasure, saving damsels, fighting enemies, and dodging traps.

In the tutorial, the player starts off playing as Yang, who leaves a journal which is found by the next Spelunker, who is later confirmed in the second game to be known as Guy Spelunky.

Levels are randomly generated and grouped into four increasingly difficult "areas", each with a distinctive set of items, enemies, terrain types and special features.

Enemies include animals like bats, snakes and spiders of varying sizes, other characters, and monsters like yeti, man-eating plants and ghosts.

The Xbox Live Arcade, as well as the PlayStation Network versions of the game feature local multiplayer (co-op and deathmatch) for up to four players.

[13] Most of these were available via the forums on the website for Derek Yu's video game company, Mossmouth, where a list was maintained of finished mods.

[2] Spelunky draws from La-Mulana, Rick Dangerous, and Spelunker for its visual styling, character design, gameplay elements and general mechanics.

[15] Essentially a dungeon crawl, it also adds elements from the roguelike genre,[16][17] including randomly generated levels, a lack of save points, frequent and easy death, and discovery mechanics.

Even Edmund McMillen, a notable game developer who created successfully challenging games such as Super Meat Boy, told him that the starting area's arrow traps should do less damage, but Derek was adamant that the immediate difficulty was necessary to show players not already familiar with the roguelike structure that death and failure is an expected part of gameplay.

[14] Destructibility of terrain was also a key element of the level design in Spelunky inspired by the pickaxe's abilities in another roguelike game called NetHack.

Derek associated his enemy design with the behavior of the ghosts from Pac-Man and how they differed their approaches to interacting with the player but collectively provided a unified and diverse experience.

[14]IGN gave the XBLA version a score of 9.0 and an Editor's Choice award, calling it "a superb 2D platformer that's as easy to hate as it is to love".

[29] 1UP.com gave the game an A ranking, saying "it offers the same immediate, pick-up-and-play fun of Geometry Wars, but demands much more than the simple reflexive reactions of your lizard brain".

[46] Referred to as "Spelunky" in Super Meat Boy, the character has the special power of explosive jumps (referencing the bombs he carries in the original game),[46] and he is exclusive to the Xbox Live Arcade version.