The Pawn
    Zork I
    Mainframe Zork
    Lord of the Rings
    Colossal Cave
    Top 5 feelies
    On collecting
    8-bit cover art
    Speech synths


Mapping the Colossal Cave Adventure

Cave is the daddy of them all. The entire genre of text adventures, or interactive fiction as it is called nowadays, rests on this game. On this page, a number of variants of this game are enumerated and discussed briefly. The object is to compare their geographical lay-outs; it's a work in progress, and it's done for my own amusement.


A brief background
Some versions and ports

A brief background

The history of the Colossal Cave Adventure computer game has been related in great detail elsewhere (here, here and here, for example), but here follows an abridged outline.

The Colossal Cave adventure is a digital version of the Bedquilt Cave, part of the Mammoth Cave system in Kentucky USA (not the Colossal Cave near Tucson, Arizona, despite the name). Will Crowther, a computer programmer and caving enthousiast, played a significant role in mapping these caves and subsequently wrote a game in FORTRAN on a DEC PDP-10 mimicking the lay-out of the caves as an amusement for his daughters. The game was called Adventure. In it, the player could travel between locations (now referred to as "rooms") and manipulate objects in order to solve puzzles by entering one or two-word commands through the computer keyboard. This form of gaming where the player's input resembles natural language became known as a "text adventure", and later "interactive fiction".

Colossal Cavern, with Bedquilt cave
Map of Colossal Cavern, with "Bedquilt route" in the right and middle of the map. From the 11th edition of Encyclopaedia Brittanica (now in the public domain).

The game was subsequently encountered by and expanded upon (with permission from Crowther) by Don Woods, a student at Stanford University, who added rooms as well as functionality. This was also the first version of the game to be called the Colossal Cave Adventure. From then on, the game found fame and success. Initially with the relative few who had access to machines like the PDP-10 that were connected to the ARPANET, but eventually the Colossal Cave Adventure was ported to smaller machines such as mini computers and home computers. At the same time it evolved into many different versions with rooms and elements added by other programmers. Different versions were often referred to by the number of points a player could earn by finding treasure. Crowther's original game did not feature a points system, Woods' version awarded a maximum of 350 points, and later games were expanded to 430 points, or 550 points, or 551 points, et cetera.

It has been said that once Woods' version became known and available, regular work on many ARPANET computers stopped for two weeks as users tried to solve it (to counter this phenomenon a blocking routine was introduced so that the game could only be played outside office hours). The prose of the game itself has become part of hacker lore. "A huge green snake bars the way", "xyzzy", "twisty passages", and the notion of dwarfs coming out of nowhere and attacking you by throwing axes are phrases that can be encountered in discussions not otherwise related to Colossal Cave.

With the advent of games consoles and home computers, game publishers undertook to port existing video games to these machines. Space Invaders, Pacman, and other successful arcade games were obvious candidates, but the Colossal Cave adventure was also picked up by several developers. The text adventure form was used and continued by a number of developers in the 1970s and 1980s to make new games with different themes — Infocom, Magnetic Scrolls, Adventure International, and Level 9 are some of the best known ones. After the commercial demise of the text adventure in the second half of the 1980s new games were and are still being produced by enthusiasts who due to the nature of the text game have no need of teams of coders, the latest hardware, and marketing campaigns.

Some versions and ports

As mentioned above, the long history of the Colossal Cave Adventure has resulted in many different versions. The original game was written in FORTRAN, then ported to C, or to assembly language for smaller machines, and finally to dedicated languages for interactive fiction such as TADS and Inform.

The object of this page is to highlight a number of variants, and to compare their respective geographies in the form of one map per version. This is a work in progress and may take a while to develop. In the meantime, I will update this page (un)regularly. The games are listed below and appear in order of the year of their original appearance (but later reconstructive ports will be listed immediately following the original).

One final note: Colossal Cave Adventure is and has been referred to by different names (Colossal Cave, Adventure, ADV, ADVENT), and these are used here interchangeably. At willy-nilly, one might say.

Crowther's ADV on PDP-10 (1976)

Presumed lost for many years, the FORTRAN source code of Crowther's original game was found again in 2007, in a backup of Don Wood's student account at Stanford University. This source was used to build a binary that could once again run on a PDP-10 computer. This text file contains some pointers to how to use SIMH to set up a PDP-10 emulator with the TOPS-10 operating system, and run the original Colossal Cave Adventure. Crowther's Cave on PDP-10ADV played on the SIMH PDP-10 emulator. Consider using cool-retro-term for added atmosphere.

This early game has a smaller vocabulary and keeps no score. Commands should be entered in capital letters. "HELP" is understood, but "INFO" is not, and to quit the game, use <CTRL>-C.

Crowther's ADV Inform 7 port (2015)

Chris Conley coverted Crowther's FORTRAN source code to Inform 7. In this form the game can be played on modern computers using a so-called interpreter. Although the game itself is a port of the original, some more modern features are implemented that serve the player in a non-intrusive way. A status bar, an undo command, a normal save-and-restore scheme, and upper and lower case text output for example. Crowther's Cave through the Frotz interpreterInform 7 port of Crowther's ADV played using the Frotz interpreter.

This version can be downloaded from the Z-code directory of the IF Archive. Look for a file named "Advent_Crowther.z8."

Woods' ADVENT on PDP-8 (1977)

As related above, Don Woods came across Crowther's game and after asking Wood's permission, added rooms and magical items to the game. A scoring system was added as well. The version shown here runs on OS/8 on a PDP-8, again through the SIMH emulator (but note that Colossal Cave was developed on a PDP-10, not on a PDP-8). This text file enumerates steps necessary to run this setup. Woods' ADVENT on PiDP-8Woods' ADVENT played on a PiDP-8, here again a cool-retro-term experience.

The image at the top of this page shows a PiDP-8, a recreation of the front panel of the original machine that works in combination with SIMH, running ADVENT. The moving "blinkenlights" on the front panel lend an almost arcade-like urgency to the experience.

Woods' ADVENT Inform port (2006)

This version describes itself as "fairly close to the [Woods' 350-point] original." The Infocom-style help section includes the output of the "help" command in the original, but also the relates the background of the game, including the history of the exploration of Mammoth Cave in Kentucky. Having been rewritten in Inform there are the usual modern features, like in the port of Crowther's ADV. Woods' ADVENT through the Frotz interpreterInform port of Woods' ADV played using the Frotz interpreter.

This version can be downloaded from the Z-code directory of the IF Archive. Look for a file named "Advent.z5."

Apple Adventure on Apple II (1980)

Being one of the first commercially offered implementations of Colossal Cave Adventure, Wood's 350-points version was ported to the Apple II computer by Peter Schmuckal and Leonard Barschack, and published by Apple Computer Inc. This version features an opening screen showing (presumably) the fierce green snake in the familiar Apple II composite artifact colors. No other illustrations appear during gameplay. Apple Adventure on IBM PCColossal Cave ported to the Apple II. Played here on the microm8 emulator.

The packaging of Apple Adventure is a simple affair, consisting of a generic Apple-themed cardboard front with one 5.25" floppy disk and a manual tucked in the back.

Microsoft Adventure on IBM PC (1981)

Another early commercial offering is Microsoft's port of Wood's 350-points version, published as a commercial product by IBM for their new Intel 8088-based IBM PC. This version was ported by Gordon Letwin and produced by Microsoft. It came on a 5.25" diskette and was a so-called booter; i.e. it did not require PC-DOS, but the computer could be started from the game disk. An earlier version came out in 1979 for the TRS-80. Microsoft Adventure on IBM PCColossal Cave ported to IBM PC. Played here on the DosBox emulator.

As can be seen in the screenshot a 40-character line screen mode was used, which doesn't seem to help to make the text more readable. Oddly, it is mentioned in the introduction screen that "This is a complete version of the M.I.T. * Adventure *", but Woods was at Stanford when he first started working on his expanded version of the game and later moved to Xerox. It may be that the producer confused Colossal Cave Adventure with Zork, another well-known early game in the ganre which was first developed at M.I.T.

Classic Adventure by Abersoft/Melbourne House (1982)

This (abridged?) 210 point version was originally known as Adventure 1 and coded by Abersoft for the Sinclair Spectrum in 1982. It was later licensed by Melbourne House (best known for their The Hobbit text adventure), renamed Classic Adventure, and ported to other 8-bit platforms, such as the Commodore 64, BBC Micro, and the Amstrad CPC. Like many games in this period for 8-bit computers, the packaging consisted of a standard cassette case. Instructions are printed on the J-card. Sinclair ZX Spectrum version of Classic AdventureClassic Adventure on the ZX Spectrum. Played here using the Fuse ZX Spectrum emulator.

Colossal Adventure by Level 9 (1983/1986)

Level 9 was a British software company that produced a large number of text adventures for a wide range of computer platforms. The first game they published was a port of Colossal Cave, expanded both under ground and above. One of the earlier packagings of Colossal Adventure included a nifty poster depicting the interior of the cave and several actors, such as the fierce green snake. Level 9 produced two sequels to Colossal Adventure: Adventure Quest and Dungeon Adventure, which were set in the same universe. Colossal Adventure for the Acorn BBC MicroThe earlier text-only edition of Level 9's Colossal Adventure on the BBC Micro in the glorious Mode 7 "teletext" typeface. Played here using the BeebEm emulator.
In 1986, these three games — now augmented by vector graphics — were reissued by publisher Rainbird as a single title, Jewels of Darkness. The bright blue box of the European version is similar to the packaging of the Magnetic Scrolls games. Jewels of Darkness came accompanied by a novella, giving some background of the world in which the games takes place. Colossal Adventure on Amstrad PCWLater editions of Colossal Adventure featured graphics; the example above is from the Amstrad PCW series, in beautiful and atmospheric green. Also shown is the enlarged score space.

The Very Big Cave Adventure by CRL (1986)

An illustrated spoof of the original game, apparently written by "St. Bride's School". The environment is instantly recognizable, yet riddled with new and positively silly puzzles. One of the few Cave incarnations that features graphics (which themselves are reminiscent of the type that are used in Level 9 games or those in Twin Kingdom Valley). C64 version of the Very Big Cave AdventureA screenshot of the Commodore 64 version of the Very Big Cave Adventure. Shown here is the famous opening scene near the well house in the forest.

The cover art is made in a somewhat primitive "comic" style. On the reverse of the inlay is an amusing rendition of the game's genesis ("Those sniffy individuals who think that adventures are superior to mindless alien-zapping obviously never played this one"). This title came out on cassette in a clamshell box for Commodore 64, Sinclair ZX Spectrum, and various Amstrad machines.

Open Adventure by Eric S. Raymond (2015)

Hacking luminary Eric S. Raymond presides over the Open Adventure, an initiative to translate version 2.5 of Colossal Cave Adventure to the C programming language. Crowther and Woods had continued working on their game after 1977; version 2.5 appeared in 1995 and was 430 points long. The puzzles Open Adventure on LinuxOpen Adventure, compiled and run on Debian Linux.

There are no modern features added to the game's engine. There is no status line to indicate the player's location and his score, and the parser still works with commands consisting of one or two words.


  • The Wikipedia entry is a good place to start reading about Colossal Cave.
  • An extensive discussion of the game's origins can be found at Digital Humanities.
  • One of the oldest pages devoted to Colossal Caves is here.
  • Open Adventure is a recent port of the final official version by the original authors.
  • The Interactive Fiction Archive holds many text adventures, amongst others a number of Colossal Caves renditions.

(Originally published 2023/01/06)