AI Dungeon

AI Dungeon is a free-to-play single-player and multiplayer text adventure game which uses artificial intelligence to generate unlimited content. It also allows players to create and share their own custom adventure settings. The game's first version was made available on Colab in May 2019, and its second version (initially called AI Dungeon 2) was released online and for iOS & Android in December 2019. The AI model was then upgraded in July 2020.

AI Dungeon
AI Dungeon Logo.png
Developer(s)Nick Walton, Latitude
Designer(s)Nick Walton
  • Windows, macOS
  • December 5, 2019
  • Android, iOS
  • December 17, 2019
Genre(s)Interactive fiction
Mode(s)Single-player, multiplayer


Gameplay screenshot from the second version of AI Dungeon (originally known as AI Dungeon 2).

AI Dungeon is a text adventure game; however, unlike traditional text adventure games, which use pre-written content,[1] AI Dungeon uses artificial intelligence to generate effectively limitless open-ended storylines.[2][3][4]

When first beginning the game, players are greeted by the following opening:

"You're about to enter a world of endless possibilities, where you can do absolutely anything you can imagine.... Will you proceed?"[5]

Players are then prompted to choose a setting for their adventure (e.g. fantasy, mystery, apocalyptic, cyberpunk, zombies),[6][7] followed by other options relevant to the setting (such as character class for fantasy settings).[8]

After beginning an adventure, there are three main interaction methods that can be chosen for each of the player's pieces of text input:[9]

  • Do: Must be followed by a verb, allowing the player to perform an action.
  • Say: Must be followed by dialog sentences, allowing players to communicate with other characters.
  • Story: Can be followed by sentences describing something that happens to progress the story, or that players want the AI to know for future events.

The game's artificial intelligence allows it to adapt and respond to almost any action entered by the player.[10]

Providing blank input can also be used to prompt the AI to generate further content, and the game also provides players with options to undo/redo or modify recent events, in order to improve the game's narrative.[11] Players are also given an option to explicitly tell the AI what elements to "remember" for reference in future parts of their playthrough.[12]

User-generated contentEdit

In addition to the pre-configured settings available in AI Dungeon, players also have the ability to create entirely custom "adventures" from scratch, simply by describing the setting in text format. The AI will then generate a setting, based on the user's input.[9][6]

Custom adventures that players create can also be published for others to play through in their own way. The game provides an interface for browsing published adventures, along with the ability to leave comments and upvote/like each one.


AI Dungeon also features a multiplayer mode, whereby different players each have a dedicated character, and can take turns interacting with the AI within the same game session. This supports both online play across multiple devices or local "pass-n-play" style using a shared device.[13][14]

Unlike the single-player game, in which actions and stories use second person narration ("you..."), multiplayer game stories are presented using third-person narration.[14]

Each game's host player is given additional permissions (likened to that of a Dungeons & Dragons Dungeon Master) whereby they can supervise the AI and make modifications to its output.[13][14]


AI Dungeon also provides players with the ability to set their adventures within specific 'Worlds', which give context to the broader environment in which the adventure takes place.[15] This feature was first released with two different worlds available for selection:

  • "Xaxas is a world of peace and prosperity. It is a land in which all races live together in harmony."[15]
  • "Kedar is a world of dragons, demons, and monsters."[15]

Premium featuresEdit

The game also features additional functionality for players who pay for a monthly premium subscription, such as:

  • Access to the advanced Dragon AI model.[16]
  • Text-to-speech functionality to provide audio narration.
  • Custom scripts when creating adventures.
  • The ability to configure advanced settings, such as the length and randomness level of responses.

Artbreeder contentEdit

AI Dungeon also provides the ability for players to select a premade avatar for themselves which were generated by Artbreeder, an artificial intelligence website which uses generative adversarial network (GAN) technology to combine and synthesize images.[17]


AI Dungeon Classic (Early GPT-2)Edit

Screenshot from the first version of AI Dungeon (also known as AI Dungeon Classic).

The first version of AI Dungeon (sometimes referred to as AI Dungeon Classic[18][19]) was designed and created by Nick Walton of Brigham Young's 'Perception, Control, and Cognition' deep learning laboratory[10] in March 2019,[9] during a hackathon.[20][21] Before this, Walton had been working as an intern for several companies working in the field of autonomous vehicles.[10]

This creation used an early version of the GPT-2 (Generative Pretrained Transformer 2) natural-language-generating neural network, created by OpenAI,[22][23] allowing it to generate its own original adventure narratives.[5] During his first interactions with GPT-2, Walton was partly inspired by the tabletop game Dungeons & Dragons (D&D), which he had played for the first time with his family a few months earlier:[20][14][18]

“I realized that there were no games available that gave you the same freedom to do anything that I found in [Dungeons & Dragons][14] ... You can be so creative compared to other games."[20]

This led him to the question:[14]

"What if you could make an AI dungeon master?"[24]

However, despite this focus on player freedom, unlike later versions of AI Dungeon, the original did not allow players to specify any action they wanted. Instead, it generated them a finite list of possible actions to choose from.[19]

This first version of the game was released to the public in May 2019.[18][10] It was released within Google Colab (an online Google tool for data scientists and AI researchers, which allows for free execution of code on Google-hosted machines[25][10]); however, it required the downloading of the full model for each player (a size of 5 gigabytes at the time).[10] Within days of the initial release, this mandatory download resulted in bandwidth charges of over $20,000, forcing the temporary shut-down of the game until a peer-to-peer alternative solution was established.[10]

This initial version is not to be confused with another GPT-2-based adventure game, GPT Adventure, created by Northwestern University neuroscience postgraduate student Nathan Whitmore, trained using 1970s text-based games (such as Zork),[26] and released (also on Google Colab) several months after the public release of AI Dungeon.[27][28]

Reflecting later, in July 2020, on the first version of AI Dungeon, its creator, Walton, stated that:

"The first version of AI Dungeon was entertaining in its own wacky way, but it could almost never form a cohesive story ... it was nothing like what it’s become today."[21]

AI Dungeon 2 (Full GPT-2)Edit

In November 2019, a new, 'full' version of GPT-2 was released by OpenAI. This new model included support for 1.5 billion parameters (which determine the accuracy with which a machine learning model can perform a task[29]), compared with the 126 million parameter version used in the earliest stages of AI Dungeon's development.[24][22] The game was recreated by Walton, leveraging this new version of the model, and temporarily rebranded as AI Dungeon 2.[22][30]

AI Dungeon 2's AI was given more focused training compared to its predecessor, using genre-specific text.[18] This training material included approximately 30 megabytes of content web-scraped from (an online community website of content inspired by interactive gamebooks, written by contributors of multiple skill levels, using logic of differing complexity[31])[32] and multiple D&D rulebooks & adventures.[33]

Initially, the new version was released as open-source software available on GitHub;[34] however, in December 2019, it became closed-source, proprietary software and was relaunched by Walton's startup development team, Latitude (with Walton taking on the role of CTO[23]).[35] This relaunch included both a new web-based interface on December 5[36][9] and mobile apps for iOS & Android (built by app developer Braydon Batungbacal[10]) on December 17.[37][38] Other members of this team included Thorsten Kreutz for the game's long-term strategy, and the creator's brother, Alan Walton, for hosting infrastructure.[10]

At this time, Nick Walton also established a Patreon campaign to support the game's further growth (such as addition of multiplayer and voice support,[10] along with longer-term plans to include music and image content[10]) and turn the game into a commercial endeavor, which Walton felt was necessary in order to cover the costs of delivering a high-quality version of the game.[20][10] AI Dungeon was one of the only commercial applications to be based upon GPT-2.[7]

Following its first announcement in December 2019,[39] a multiplayer mode was added to the game in April 2020. Hosting a game in this play mode was originally restricted to premium subscribers (although any players could join a hosted game); however, it was made a free feature in July 2020.[13][14]

Dragon model release (GPT-3)Edit

In July 2020, the developers introduced a premium-exclusive version of the AI model, named Dragon, which uses OpenAI's new API for leveraging the GPT-3 model without maintaining a local copy (released on June 11, 2020[33]).[40][21] GPT-3 was trained with 570 gigabytes of text content (approximately one trillion words, with a $12 million development cost[7]) and can support 175 billion parameters, compared to the 40GB of training content and 1.5 billion parameters of GPT-2.[41][23] This upgrade allowed AI Dungeon to maintain a much more coherent story than previously possible.[42][43]

The free model was also upgraded to GPT-3, albeit a less advanced version, and was named Griffin.[21]

Speaking shortly after this release, on the differences between GPT-2 and GPT-3, Walton stated:

"[GPT-3 is] one of the most powerful AI models in the world[1] ... It's just much more coherent in terms of understanding who the characters are, what they’re saying, what’s going on in the story and just being able to write an interesting and believable story."[7]

In the latter half of 2020, the 'Worlds' feature was added to AI Dungeon, providing players with a selection of overarching worlds in which their adventures can take place.[15]


Approximately two thousand people played the original version of the game within the first month of its May 2019 release.[18][10] By contrast, within a week of its December 2019 relaunch, the game reached over 100,000 players and over 500,000 play-throughs,[22] and reached 1.5 million players by June 2020.[24]

As of December 2019, the game's corresponding Patreon campaign was raising approximately $15,000 per month.[9]

GPT-2 edition reviewsEdit

In his January 2020 review of the GPT-2-powered version of AI Dungeon (known at the time as AI Dungeon 2), Craig Grannell of Stuff Magazine named it 'App of the Week' and awarded it 4 out of 5 stars. Grannell praised the game's flexibility and its custom story feature, but criticised the abrupt shifts in content that were common in the GPT-2 edition of the game:[4]

[AI Dungeon is] an endless world of dreamlike storytelling, and a fascinating glimpse into the future of AI.[4]

Campbell Bird of 148Apps also awarded this edition of the game 4 out of 5 stars in his review, also praising its creativity whilst criticising the lack of memory for previous content:[44]

AI Dungeon is like doing improv with a partner who is equal parts enthusiastic and drunk ... [It] is a game that’s charming, occasionally frustrating, but mostly just impressive in its raw creativity and spirit.[44]

Jon Mundy of TapSmart awarded it a 3 out of 5 star rating, similarly praising its variety and the "magical" custom adventure option, but described its adventure narratives as "often too passive and vague" and lacking in resolution.[6]

Creating non-game contentEdit

In addition to those who used AI Dungeon for its primary purpose as a game, other users experimented with using its language generation interface to create other forms of content that would not be found in traditional games (primarily via the custom adventure option). Although the game was primarily trained using text adventures, training content for the GPT models themselves included large amounts of web content (including the entirety of the English-language Wikipedia[45]), thereby allowing the game to adapt to areas outside of this core focus.[7] Examples of AI Dungeon being used in this way include it:

External linksEdit


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  3. ^ Vincent, James (December 6, 2019). "This AI text adventure game has pretty much infinite possibilities". The Verge. Retrieved December 10, 2019.
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