You might want to check the grammar of the second sentence.
that the file format will most certainly change before release
I would have objected against this wording a few moments ago, but since I just broke the saved game format for 0.30.0, that does not apply anymore.
so save files may become obsoleted in future versions.
That on the other hand is a very unusual wording. If I did not know, what it meant, I may not have understood it.
If we want to go more into detail, then we should list the parts that are not saved yet:
- Player controls enable/disable
- weather
- some creature state, including all magic (also used by NPCs)
- movement of objects between cells (except for the player)
- fog of war