A modern reimagining of the classic text adventure Adventure 2.5 / Open Adventure
with a touch-friendly interface and a forgiving natural language parser.
CCA is a reimagining of the classic text adventure Adventure 2.5 / Open Adventure but with a modern touch interface and an improved text parser. This was created by Nathan Pitman as an opportunity to explore what's possible with modern AI led development and a healthy dose of childhood nostalgia.
This is an original game in terms of code, but it uses the cave structure, objects, and descriptions found in the historical Adventure text-adventure — Open Adventure's port of Adventure 2.5.
CCA has been prompted using ChatGPT and Replit on Apple iOS (iPhone & iPad).
The standout feature of CCA is its custom-built natural language processing (NLP) text parser, designed to make the game far more forgiving and accessible than classic text adventures. Rather than demanding exact two-word commands, players can type naturally and still be understood.
Natural language input — Type full sentences like "pick up the golden key", "go through the door", or "use the key on the rusty grate". The parser breaks down sentence structure, identifies verbs, objects, targets, and prepositions automatically.
Stopword & article stripping — Filler words like "the", "a", "please", "just", and "some" are silently removed so casual, conversational input works as well as terse commands.
Rich verb synonyms — Dozens of synonyms are mapped to canonical verbs. For example, "grab", "snag", "retrieve", "collect", and "pick up" all resolve to take. Similarly, "inspect", "examine", "observe", and "where am I" all resolve to look.
Direction & movement synonyms — Compass shortcuts (n, s, e, w, ne, sw, etc.), full words (north, south), suffixed forms (northward, upwards), and natural phrases like "follow the stream downstream" or "climb up" are all understood.
Narrative location synonyms — Descriptive phrases are mapped to game locations, so "follow the stream", "down the stream", "crawlspace", "staircase", "passageway", "corridor", and many more resolve to the correct destination.
Noun & object synonyms — Multiple names for the same thing work interchangeably. For example, "building", "house", and "wellhouse" all refer to the same location. "Cavern" and "cave" are equivalent, as are "crevice", "fissure", and "crack".
Fuzzy matching with typo correction — A Damerau-Levenshtein edit-distance algorithm tolerates up to 2 character typos. If you mistype a command, the parser auto-corrects and tells you what it did — e.g. (interpreting 'lampp' as 'lamp').
Keyboard-proximity-aware matching — On top of standard edit distance, a QWERTY-aware algorithm recognizes that typos caused by hitting a neighboring key are more likely than distant key substitutions. Adjacent-key swaps (like o↔p, i↔u, t↔y) are penalized at half the cost of unrelated character swaps. This means "go pit" correctly resolves to "go out" because p is next to o and i is next to u on the keyboard — even though standard edit distance treats all substitutions equally.
"Did you mean?" suggestions — When the parser is less confident about a fuzzy match, it offers a helpful suggestion instead of a dead end — e.g. "You don't see that here. Did you mean 'keys'?"
Singular & plural normalization — "keys" matches "key", "torches" matches "torch". The parser automatically generates singular and plural word forms so either version works.
Structured multi-object commands — Complex verb-item-preposition-target patterns are fully supported: "unlock the chest with the key", "throw the axe at the dwarf", "pour water on the plant", and similar constructions all parse correctly.
Context-aware action resolution — The resolver doesn't just parse words — it checks what actions are actually available in the current scene and what items are in your inventory before matching. This prevents impossible actions and provides meaningful feedback.
Inventory-aware fuzzy matching — When you type "use" or "drop", fuzzy matching runs specifically against items you're carrying, so near-misses resolve to the right object in your bag rather than something elsewhere in the cave.
Magic words & classic adventure verbs — All the classic Adventure magic words are supported: xyzzy, plugh, fee/fie/foe/foo/fum, sesame, abracadabra, shazam, and more — typed as bare words or with "say" / "speak".
Lamp toggle patterns — Many natural ways to control the lamp are recognized: "turn on the lamp", "light the lantern", "extinguish torch", "douse lamp", and all variations across lamp/lantern/torch synonyms.
Flexible meta-commands — Inventory can be checked with "i", "inventory", "bag", "backpack", "what am I carrying?", or "my items". Help can be accessed with "?", "help", "commands", or "how to play".
This project takes inspiration from:
- Open Adventure — a modern C forward-port of the Adventure 2.5 codebase originally developed by Will Crowther and Don Woods, updated and maintained by Eric S. Raymond and contributors. LibreGameWiki
While this project does not reuse code from the Open Adventure repository, it references the cave structure and object descriptions that have been historically part of the Adventure lineage.
This project is released under the 2-Clause BSD License.
Based on the Open Adventure project (forward-port of Adventure 2.5, originally by Will Crowther & Don Woods, modernized by Eric S. Raymond et al.).
This project was inspired by:
- Open Adventure — forward-port of Adventure 2.5 (1995) under the 2-Clause BSD License. LibreGameWiki
If you find bugs, would like to contribute, or have questions about this project, please open an issue or contact me via hello@nathanpitman.com.