Alt-F10 is reliable, yes, because it only works in places where you're allowed to save (try pressing it while evolving, for example, and it does nothing).
Alt-F4 is a system command that shuts down the program, and I decided to have that save your game as well, but that executes
anywhere, and skips the saving if saving is not possible in the given game state. I'd prefer players not use Alt-F4, hence the lack of documentation, but added the feature anyway