> Also, it's the same model for all the games, right

It's a bit unclear but it looks like different models, since they all have different parameter and MAC counts. It would be much more impressive with a single world model that could maybe dream up new games inbetween the games in the training set.

It's a self contained net for each game but the data used for training doesn't overlap with the validation. I think it would be easy to merge them into a single model