The tool calling part might be doable (though I’ve personally struggled to get it working passably with local models), but if the goal is to tell a compelling story or create an interesting experience, especially if doing so in a very open ended way, that isn’t trivial. The only LLM based game I’ve personally played that seemed good was mostly on rails and partially scripted, most of them just aren’t very interesting to play, because the model doesn’t have a good idea where it’s going with anything and is often not very creative, the stuffy personality of the instruct model seems to infect the dialogue and apparent thought process of the characters. For a specific example I’d recommend watching streams of the game Suck Up, which has a genuinely cool concept and solid execution, but you can see people being frustrated running into its limitations as something to interact with creatively.

I’ve tried a couple times to start game projects involving LLMs, and get the feeling that there is a lot of exploration that needs to be done into what can be done well and where that intersects with what is actually fun. Kind of don’t expect EA to be the one to do that.