If I were to create a new game from the ground up, with new artistic assets, and not an LLM in sight, with the characters of Luke Skywalker and Darth Vader playing around on the Millenium Falcon, I would be breaching copyright.

I'm not sure if look and feel of a game like Transport Tycoon can be copyrighted, but I wouldn't like to be against it.

(I remember buying Transport Tycoon from I think Beatles, in Altrincham. I clearly remember riding on the front seat of the bus upstairs on my way to Flixton back in 1994 reading the manual)