Did a bunch of work on this yesterday and this morning. Obviously needs some more work, but besides the alterworld tile layout getting messed up in the translation, it's OK so far. This is not two different tilemaps objects being swapped in and out of memory, but rather one tilemap having its settings modified based on serialized binary data that I generated with a script. Here I've set the swap to buttons for testing (might want to include this as a feature in debug mode). I have to optimize the swap more since there's still a slight freeze (that freeze would not exist if the swap happened over several frames as I said before, but I'd still like it if an instantaneous, no-lag swap was possible), and figure out a way to carry over animated environmental details like flowers. I'll probably change the flowers to work like enemies where it's a single sprite that gets changed when the transition occurs, rather than before where the flowers and similar animated details were set as children of their respective worlds