> As long as they are operating over an immutable view of the game state That's a big issue. There is a surprising amount of back and forth between objects in

> As long as they are operating over an immutable view of the game state That's a big issue. There is a surprising amount of back and forth between objects in a single step of gameplay/AI. And, generally gameplay code tends to be a big mess of wild and ever-changing requirements from gameplay designers, extreme time crunch and short term (1 game then burn it) goals. Ivory tower software architecture it is not... Clustering physics into "islands" is common practice though.