Colossal Cave Adventure

Jerz > Interactive Fiction > Colossal Cave Adventure | Will Crowther’s Original ‘Colossal Cave Adventure’ Source Code ]

“Adventure” (also known as “Colossal Cave Adventure”) is a forerunner of virtual reality, and as such, is a forerunner of all kinds of hyper narrative, digital storytelling, and computer games. For a game that seems (to our jaded eyes) unfair, stylistically inconsistent, and frustrating, it has been tremendously influential.  Colossal Cave Adventure was the first of its kind — a novel way to use code and words to create a  rich simulated world.  Nobody had seen anything like it; it spread quickly across the Internet.

In early 1977, Adventure swept the ARPAnet. Willie Crowther was the original author, but Don Woods greatly expanded the game and unleashed it on an unsuspecting network. When Adventure arrived at MIT, the reaction was typical: after everybody spent a lot of time doing nothing but solving the game (it’s estimated that Adventure set the entire computer industry back two weeks), the true lunatics began to think about how they could do it better [proceeding to write Zork](Tim Anderson, “The History of Zork — First in a Series” New Zork Times; Winter 1985)

[play Colossal Cave Adventure online]

Some sources date the origin of Colossal Cave to 1972, on the grounds that Crowther was at that time keeping a computer map of the real Mammoth Cave.  While Woods is sometimes credited for turning Crowther’s map into a game, Crowther’s original definitely had treasures and puzzles.  In an e-mail to me, Crowther noted that he originally intended for the magical elements to be buried deep within the cave, but that Woods introduced the magic much earlier.


Fig. Adventure 1-1 (Gillogly?)

Welcome to Adventure!! Would you like instructions?

Somewhere nearby is Colossal Cave, where others have found fortunes in treasure and gold, though it is rumored that some who enter are never seen again. Magic is said to work in the cave. I will be your eyes and hands. Direct me with commands of 1 or 2 words. I should warn you that I look at only the first five letters of each word, so you’ll have to enter “northeast” as “ne” to distinguish it from “north”. (Should you get stuck, type “help” for some general hints. For information on how to end your adventure, etc., type “info”.)
– – –
This program was originally developed by Will Crowther. Most of the features of the current program were added by Don Woods. Address complaints about the UNIX version to Jim Gillogly (

You are standing at the end of a road before a small brick building. Around you is a forest. A small stream flows out of the building and down a gully.

The transcript above is from one of many versions floating about the Internet. According to Adams (“A History of ‘Adventure’“), Jim Gillogly “spent several weeks in 1976 porting the code (with Woods’ and Crowther’s blessings) from the original FORTRAN source into C for UNIX. Most UNIX systems run successors of this C version.” As part of the Software Toolworks edition in 1981, Walt Bilofsky “added another puzzle, the stock certificates,” (Gillogly, e-mail to the author, 15 Apr 2000) and the game was marketed under the name “The Original Adventure.”  Gillogly recalls: “At my insistence the Toolworks paid them [Crowther and Woods] a royalty in exchange for their endorsement of it, and so far as I know these royalties are the only money they made out of the program.”

The opening text, presumably written by Gillogly, gives more credit than usual to Don Woods.  “Most of the features of the current program were added by Don Woods” may be an exaggeration, unless Gillogly meant “features” in the sense “new features, not found in the previous version.”   According to Gillogly:  “The original version I wrote was very much like the Crowther and Woods version: I used their Fortran source, and changed only one aspect of Witt’s End, to make that point less obscure.”

Gillogly continues:

The original port was quite faithful to the original, including retaining the upper case text. As part of the port to the Software Toolworks version on the Heathkit H-89 I switched to upper and lower case, and changed the wording after victory to be more satisfying than just the “OK, it’s over” kind of thing. Crowther and Woods played this version and agreed that it kept the flavor they had in mind.

Fig. Adventure 1-2 (Inform)

At End Of Road
You are standing at the end of a road before a small brick building. Around you is a forest. A small stream flows out of the building and down a gully.>enter building

That’s not something you can enter.>open door
You can’t see any such thing.>go in
What do you want to go in?>building
That’s not something you can enter.>in
Inside Building

To further complicate the matter, there are so many different versions of this game floating around the Internet, including versions that have been expanded by authors of uneven quality, that establishing the “definitive” version is still a bit tricky. A sequence of commands that works in one version of “Adventure” may not work in another version.

For example, in the Gillogly version, typing “enter building” at the beginning of the game successfully moves the player inside. A 1994 reconstruction by Eckman, Baggett and Nelson (fig. 1-2) improves the formatting, makes the text much easier to read, and offers loads of new features (such unrestricted saving of in-progress games, an online hint system, and more), but the simple command “enter building” no longer works.

As the transcript shows, in this implementation of “Adventure”, typing “in” will get you inside, but “go in” “open door” and “enter building” will trigger an error message that claims that the building is “not something you can enter”. The unfortunate newcomer who gets this message will be unnecessarily frustrated.

While the Gillogly version does not have the “enter” problem, it and the 1994 version both share another problem concerning a stream. The textual description of the area mentions that the stream flows “down a gully,” so one is naturally led to move in that direction, towards what appears to be a dead end.

Fig. Adventure 1-3 (Inform)

At End Of Road

You are standing at the end of a road before a small brick building. Around you is a forest. A small stream flows out of the building and down a gully.


In A Valley

You are in a valley in the forest beside a stream tumbling along a rocky bed.


At Slit In Streambed

At your feet all the water of the stream splashes into a 2-inch slit in the rock. Downstream the streambed is bare rock.


You don’t fit through a two-inch slit!


You can’t go that way.


Although the description of “At Slit In Streambed” includes the word “downstream,” when the player tries to go down again, the computer responds with a “cute” refusal message. When the player tries to go back “up,” another error message results. While part of the “fun” of any game involves discovering the rules, most players would probably agree that, if you were “really” exploring the area around Colossal Cave, you would not need to strike out in random directions to learn that one has to go south in order to move from “At Slit In Streambed” to the bare rock mentioned in the text. The textual descriptions of the various playing spaces do not provide enough of the information that the user needs in order to navigate the space. Hence, the “puzzle” of finding the grate is contrived and annoying.

Note: A reader who wishes to remain anonymous (out of respect to the creators of the 1994 edition) points out that the original version of Adventure recognized commands such as “go downstream.”  Hence, the original game did not require the player to intuit which direction to go. The reader writes:

I recall the momentary sense of wonder at this “powerful” program that could understand “GO DOWNSTREAM”. And then, I forgot about the programming challenge and was immediately drawn into the story (OK, game). It was my first taste of mimesis. I’m sad for all those who’ve only experienced the port and not experienced this moment of magic right at the beginning of the experience. — An anonymous commenter, in a personal e-mail to me, 23 Mar 2001.

“Colossal Cave Adventure” created a new literary genre, provided a generation of programmers with their first taste of a natural-language interface, and, with its focus on exploring and collecting treasure in an underground setting, continues to influence computer games.



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