Colossal Cave Adventure (also called Adventure or ADVENT) is a text-based game created in 1976 by Will Crowther for the PDP-10 mainframe computer. Don Woods added more content to the game in 1977. In the game, players explore a cave system said to contain treasure and gold. The game has many locations, and players move between them and interact with objects by typing one- or two-word commands. These commands are understood by the game’s system, which acts as a narrator, describing the player’s location and the results of their actions. It is the first widely known example of interactive fiction and the first well-known adventure game, after which the genre was named.
The original game, developed in 1975 and 1976, was based on Crowther’s maps and experiences exploring Mammoth Cave in Kentucky, the longest cave system in the world. It was designed to be easy for non-technical players, including Crowther’s daughters, to enjoy. Woods’s version made the game larger and added fantasy elements like a dragon and magic spells. Both versions were played on teleprinters connected to mainframe computers and shared across ARPANET, an early version of the internet that Crowther helped create.
Colossal Cave Adventure was one of the first teletype games and became very popular in the late 1970s. Many versions of the game were created using Woods’s code. It inspired the development of other games, including Zork (1977), Adventureland (1978), Mystery House (1980), Rogue (1980), and Adventure (1980), which became the basis for interactive fiction, adventure, roguelike, and action-adventure genres. It also influenced the creation of MUD and computer role-playing games. In 2019, it was added to the World Video Game Hall of Fame by The Strong and the International Center for the History of Electronic Games.
Gameplay
Colossal Cave Adventure is a text-based adventure game where the player explores a mysterious cave believed to hold treasure and gold. The player moves through the cave, solves puzzles, and collects treasures by using items found in the cave. To play, the player types one- or two-word commands to move, interact with objects, pick up items, and perform other actions. The available commands depend on the room the player is in; for example, "get lamp" only works if a lamp is present in that room. The game has many rooms, each with a name like "Debris Room" and a description. Some rooms contain objects or obstacles. The program describes the player's location and the results of their actions. If the program does not understand a command, it asks the player to retype it. The program's responses are usually humorous and conversational, similar to how a Dungeon Master might speak during a tabletop role-playing game.
The original 1976 version of the game includes five treasures that players can collect. While the game is based on a real cave system, it includes fantasy elements such as a crystal bridge, magic words, and dwarves who carry axes. The player can die by falling into a pit or being attacked by the dwarves, but the game has no set ending or goal other than collecting treasures. The 1977 version of the game, which later versions are based on, adds ten more treasures and more fantasy elements. It also introduces a points system, where completing certain tasks earns the player a set number of points. The main goal in the 1977 version is to earn the maximum number of points—350—which requires collecting all treasures and leaving the cave safely.
Development
Colossal Cave Adventure was first created by William Crowther in 1975 and 1976. Crowther and his ex-wife, Patricia, were both programmers and cavers. They explored Mammoth Cave in Kentucky, the longest cave system in the world, in the early 1970s as part of the Cave Research Foundation. In 1972, Patricia led an expedition that discovered a connection between Mammoth Cave and the larger Flint Ridge Cave System. The pair also made detailed maps of the cave by recording survey data from small books into a teleprinter terminal at their home. This device connected to a PDP-1 mainframe computer at Bolt, Beranek and Newman (BBN), where Crowther worked. They used this data to create a program that generated instructions for a Honeywell 316 minicomputer, which printed maps on a Calcomp drum plotter. These maps were among the first computer-drawn cave maps.
In 1975, after Crowther and Patricia divorced, he stopped caving with the Cave Research Foundation. He began creating a text-based game in Fortran on BBN’s PDP-10 mainframe, using a teletype printer. He combined his memories of Mammoth Cave, especially a 1975 map of the Bedquilt area, with ideas from Dungeons & Dragons to design a game about exploring a cave for treasure. Crowther wanted the game to be easy for non-technical players, like his children, to use. He developed a system that allowed players to use simple English-like commands. This made the game appealing to both programmers and non-programmers. The game’s design also allowed it to run on teletype printers instead of monitors.
The first version of the game had about 700 lines of code and 700 lines of data, including descriptions for 66 rooms, 193 vocabulary words, and other messages. Crowther shared the game with coworkers at BBN in early 1976 and then left it on the mainframe before taking a vacation. When he returned, he found that others had discovered and widely shared the game across ARPANET, an early computer network. The game had no official title, only the message "WELCOME TO ADVENTURE!!" and a file name of ADVENT. It was later called Colossal Cave Adventure, which became the more common name. At the time, most computers used teletype printers instead of monitors.
Don Woods, a graduate student at Stanford University, found the game on a PDP-10 computer at Stanford Medical School. He contacted Crowther to get the source code and expanded the game by adding fantasy elements like a dragon, new puzzles, and a pirate character. He also introduced a scoring system and added more treasures. Woods’s version, released in 1977, had about 3,000 lines of code and 1,800 lines of data, including 140 map locations, 293 vocabulary words, and 53 objects. He also added controls to restrict game access during business hours. Woods continued updating the game in Fortran until 1995.
Crowther did not share his version’s source code, and it was believed lost until found in 2005 in an archive of Woods’s student account. Woods shared his version’s code and executable, making it more widely available. Woods’s 1977 version became the most recognized version of Colossal Cave Adventure, partly because its code was easier to use on other systems. Both Crowther’s and Woods’s versions were designed for the PDP-10 and used features specific to that system, making them hard to move to other computers.
In 1977, James Gillogly of RAND Corporation ported the game to the C programming language for Unix systems. This version is still included in BSD and Linux distributions as "adventure." Bob Supnik of Digital Equipment Corporation also ported the game to the PDP-11 minicomputer in 1977. By 1982, many versions of the game existed, and an article in Your Computer named them "Adventure games." In 2017, Eric S. Raymond created a modern version of Woods’s 1995 game for current computers.
Legacy
Colossal Cave Adventure is considered one of the most influential video games. In 2019, it was added to the World Video Game Hall of Fame by The Strong and the International Center for the History of Electronic Games. The game is the first well-known example of interactive fiction and set standards that are now common in similar games, such as using shortened directions like "e" for "east." It also inspired the stories in later interactive fiction titles. The game is the namesake and the first well-known example of an adventure game, as it combined the interactivity of computer programs with the storytelling of literature or role-playing games like Dungeons & Dragons, even though it did not have a clear, linear story. The only text adventure game known to come before it was Wander from 1974, which did not have the same level of influence as Colossal Cave Adventure.
Colossal Cave Adventure was very popular among the small group of people who used computers in the 1970s. Historian Alexander Smith described it as "ubiquitous" on computer networks by the end of 1977, along with Star Trek and Lunar Lander. Walter Bright, creator of Empire (1977), said that Adventure "caused a sensation." Columnist Jerry Pournelle noted that employees at computer installations often lost two weeks of work when Adventure arrived because they played it. Attempts to stop people from playing the game failed; the only solution was to let everyone solve it.
Computer game programmers were greatly inspired by the game. According to Graham Nelson, creator of the Inform interactive fiction language, "for the five years to 1982, almost every game created was another 'Advent.'" Many of these games were the first releases from companies that later became key innovators in the adventure game genre. These included Zork (1977), which started development soon after the release of Woods's version, created by a team at MIT and later by Infocom; Adventureland (1978) by Scott Adams of Adventure International; and Mystery House (1980) by Roberta and Ken Williams of On-Line Systems. The 1980 Atari 2600 video game Adventure was an attempt to create a graphical version of Colossal Cave Adventure. It became the first known example of an action-adventure game and introduced the fantasy genre to video game consoles. Carmen Sandiego, an early educational game series that began in 1985, was inspired by the idea of exploring a cave to find treasure, which was transformed into a game where players search the globe for clues.
In addition to inspiring adventure games, Colossal Cave Adventure demonstrated the "creation of a virtual world and the means to explore it," as described by Matt Barton in Dungeons and Desktops: The History of Computer Role-Playing Games. It also included monsters and simplified combat, making it a precursor to computer role-playing games, even though it lacked some elements of the genre. Glenn Wichman and Michael Toy named the game as an influence for their game Rogue in 1980, which later became the namesake of the roguelike genre. Colossal Cave Adventure also inspired the development of online multiplayer games like MUDs, which are the precursors to modern-day massively multiplayer online role-playing games.
Two phrases from the game have had a lasting impact in programming and video games. "Xyzzy" is a magic word that teleports the player between two locations. It was added by Crowther in response to a request from his sister during play-testing to skip an early section of the game. As a tribute to Adventure, many later games and computer programs include a hidden "xyzzy" command, with results ranging from simple to humorous. Crowther chose "xyzzy" because he wanted magic words to look unusual but still be easy to pronounce. Additionally, the game includes a maze where each of ten room descriptions is exactly the same: "YOU ARE IN A MAZE OF TWISTY LITTLE PASSAGES, ALL ALIKE." The layout of this maze was fixed, requiring players to map it themselves. The phrase "you are in a maze of twisty little passages, all alike" became popular in hacker culture, where the word "passages" is sometimes replaced with another word depending on the situation. This phrase came to represent a situation where actions do not change the outcome.
Colossal Cave Adventure has continued to be referenced in media for decades. The 2003 book Twisty Little Passages, which focuses on the history of interactive fiction, was named after the "all alike" maze. The 2010 documentary Get Lamp, about the history of text adventure games, was named for the command to pick up the first object the player must carry to solve the game. The 2013 game Kentucky Route Zero draws direct inspiration from the game, showing a computer simulation inside a cave that depicts a massive cave system. The game is also a key plot point in an episode of the 2014 TV series Halt and Catch Fire, a drama set during the early days of the personal computing revolution. In the show, the chief software designer uses the game as a test to determine which programmers will stay on the team. A fully playable version of the game, including hints and artwork, was made available on the show's official website.