I *think* the "Lost Levels" error might've been to do with me trying to save too much data at once. The framework's save got mixed up with the level editor's save, and the data simply vanished into the ether.

I've added a "Saving" display, so that the user can't do anything whilst the save's happening. Hopefully that should solve the issue, but I'll be keeping a watchful eye on my levels!!

In the meantime, I'm ploughing ahead, and now have 16 tutorial'y levels.
I'll be adding another set of 4 tutorial'y levels, but after that the player will be left to stumble through the chaos themselves.