Colossal Cave Adventure

Colossal Cave adventure was the adventure game that gave the genre its name. It was also known as Adventure or ADVENT due to the 6 character limit of computers at the time. It was a complete text adventure, with no graphics, since the PDP-1 computer it was originally written for had no graphic output.

 It was developed between 1975 and 1976 in FORTRAN IV by Will Crowther and shared over the ARPANET (the precursor to the internet). Later that year, Matthew Russotto ported it to FORTRAN-77.

Also in 1976, Don Woods found it and expanded it with Will Crowther's permission, completing his version in 1977. The Don Woods version became quite popular, spreading over the ARPANET until it was ported to C for UNIX by Jim Gillogly. This version inspired many others to create their own games in a similar style (such as Sierra, Infocom, and Adventure International).

There were text-based games were released before it, such as Hunt the Wumpus, which was created in 1973.  Hunt the Wumpus was known for its bats which would transport the player to another room, which also appear in Colossal Cave Adventure.  However, Colossal Cave Adventure is the adventure game that popularized the genre, with its inventory and puzzles, which remain a staple in most western adventure games to this day.

The cave in Colossal Cave Adventure is based on Bedquilt Cave, a cave within the Mammoth Cave system in Kentucky, that connects to Colossal Cave. In 1972, Will Crowther's wife Patricia was part of the team that found the link that connected Flint Ridge caves to the Mammoth Cave. The Bedquilt cave was Will's favorite part of the Mammoth cave system, so he decided to make a game based around it from a map he had made, in the hopes that it would be a game that his daughters would enjoy. As he was a fan of Dungeons and Dragons, he decided to combine elements of fantasy role-playing into the game as well. In the game, you search for treasure while navigating the maze-like caverns and avoiding or fighting the creatures.

The game had the elements that would become a staple of the genre, such as story-based gameplay, puzzles, and inventory. It had a point-based system, where you're awarded a number of points out of a possible total, based on whether you accomplished certain tasks in the game. This point system would be used in the games by the companies that were formed in which the founders were inspired by the game, such as Adventure International, Infocom, and Sierra. Sierra, in particular, continued the point system well into the graphical point-and-click era of adventure gaming.

The 350 point versions of the game for PDP-1 and UNIX were released for free, and source code for a version for Commodore 64 was included in the book Exploring Adventures on the Commodore 64 by Peter Gerrard in 1983. In addition, it has also been ported to many different scripting languages, including ADRIFT, Glulx, GINAS, Hugo, TADS, and Z-code.

Some ports to other platforms have also been released commercially. A 370 point version called The Original Adventure, developed by Jim Gillogly and Walter Bilofsky, was released commercially by The Software Toolworks HDOS and CP/M in February 1982. This version was then released for DOS in February 1984.