I've been told that I post too few updates. So here is a new update :) . I'll try to post at least once a week from now on.
The campaign mode is probably the biggest single feature that I'm adding since the game's first release. In terms of code architecture, it's quite like running multiple game worlds concurrently with the option of transferring creatures around. They are arranged in an array and form the "overworld".
The most important functionality is of course slicing up the array, uploading individual chunks to the cloud, and reconnecting them on other players' computers. A few changes were needed in the game's core to accommodate this, and I'm sure that new bugs have been spawned.
The good news is that the game's performance will actually increase, because only one chunk is being simulated at a given time (the one containing the player). Other chunks are kept in memory, but are frozen. Since the chunks are about 1/4 of the size of current maps, they only occupy less than 200MB of memory each. If we stay within the limit of 5-8 main enemies per world, we are good without the need of offloading the maps to disk. (Chunks where no enemy exists are not even created).
The main reason for the "freezing" of chunks is that each one has a separate clock. Creatures thus need to change "time zones" when transferring between chunks. When a minion you are controlling is away from home, the clock at your base doesn't tick. I think that's good. There is also a global clock that dictates day and night changes.
I'm on track to make all of this work. I'll let you know when the first historical duel of Keeper vs. Keeper takes place :) .
Basic campaign setup UI