...but I think linked list were not the main problem, but (1) use of inheritance instead of composition to implement unit behaviour (but we all walked into that trap, and these were the 90's when OOP was still hip and universally seen as a silver bullet), and (2) it looks like objects have been linked to each other quite ad-hoc, instead of providing some sort of 'object relationship system' which encapsulates object linkage and querying for objects. But as I said, these were the 90's and game developers have learned from these mistakes. There's a lot of good whitepapers around about entity component systems, composition, high-level architecture of games and so on. Today it's more about asset creation pipelines and production tools, at least for 'big' game projects.