Mutators are alternate ways to play gameworlds that will be selectable once you start. For example, collision in minigolf with other balls.
IO is like Minecraft’s redstone.
It would be nice with the loading times for the plaza to add an “other” option. Sometimes I load in instantly and at other times it can take 5-10 minutes to load. This can be within the same time period and day.
Opting into the .pak branch on Steam will fix load times, so will putting the game on an SSD. However with the .pak branch, you’ll need to redownload the game content (~9GB) each update.