Indie dev builds GTA-style game with real global map data
Charlie Chapman says the project uses planet-scale weather and procedural building interiors, with most work done by Claude Opus 5.5.
Indie developer Charlie Chapman announced on X that he is building a GTA-style game from real public-domain map data at global scale, according to gamespark.jp. The project is not publicly available.
According to Chapman, the world includes planet-scale weather systems such as rain, wind and storms that players can observe. Buildings have procedurally generated interiors, and vehicles including skateboards, snowboards, planes and rockets are already implemented for travel around the world. A photo mode is also in place.
Chapman said most of the development is done with AI, using three Macs at home and the Claude Opus 5.5 model. His routine is to review and playtest what the model produced before bed, give the next instructions, then check the results the following day.
AI-assisted workflow
The setup puts the developer in a review role, approving or redirecting the model's output each day rather than building every system by hand. No release date or platform has been announced.
Quick answers
Is Charlie Chapman's GTA-style game available to play?
No. Chapman said the project is not publicly available.
What is the game built with?
Chapman said most of the development is done with AI, using three Macs at home and Claude Opus 5.5.
What features does the project include?
Planet-scale weather systems, procedurally generated building interiors, vehicles such as skateboards, snowboards, planes and rockets, and a photo mode.