It's interesting to hear that developers have found a way to use the ChatGPT API to play older games like Lara Croft Tomb Raider and Skyrim. However, it's important to note that using the API to play games might be against OpenAI's usage policies, so I would advise caution before proceeding.
Regarding the guide you mentioned, it would be helpful if someone could take a look at it and create a step-by-step guide for others to follow. However, since the use of the ChatGPT API might require payment, it might not be possible to have a completely free version.
If there is a version of ChatGPT that can be downloaded and used offline, that could be a good alternative for those who prefer not to use the API. However, please be aware that my knowledge is based on information available up until September 2021, so it's always a good idea to check for the latest updates and policies from OpenAI.
Lastly, if you're interested in exploring AI-aided gameplay or modifications further, searching for "Skyrim AI" on YouTube might provide some helpful videos and tutorials.