How it was made: Rieseberg wrote in his launch post that he made Saltline to test the quality of Claude Fable 5.2, Anthropic's model, using one-shot prompts and no human feedback. A three-minute video he posted the next day shows the prompt: a request for a small, single-level FPS with detailed, photorealistic graphics. According to the video, Claude had a written plan and a level map about three minutes in, and nobody gave feedback until the game was finished. Rieseberg said that build took 8 hours and cost about $550 at API pricing, using about 2.7 million output tokens and 445 million input tokens, most of them cached.
The version at the play link isn't that untouched build. In a note on the game's title screen, Rieseberg says he spent about two more hours on it because he wanted better weapon models and sounds and some gameplay changes. The note doesn't say how he made those changes. The one-shot version is still linked from the same screen.
For the one-shot build, Rieseberg said the models, sounds and textures were all made from scratch. In a follow-up post on X on November 10, he wrote that there are no image or 3D model files at all: the textures and models are functions, and Claude "wrote shaders" rather than drawing anything. His video shows examples, such as corrugated steel made from a cosine wave plus layered noise, container paint that chips to primer and then rusted steel, and the Hound's skeleton defined in code, with its knee angles worked out as it walks. The music is generated in layers that change with the fight. The video also says a second Claude scored screenshots of the game, and Claude revised its work in response.
Rieseberg noted that the source code sits in the page's HTML, so players can read it. These details come from his own posts, his video and the game's title screen; AIGamer hasn't reviewed the code.
