Oh, looks like someone was editing their save files, then. There's nothing to stop people from doing that. If you want to cheat like crazy you can by editing save files; only way to prevent that would be some sort of central server thing, but that's bad for a whole lot of reasons. So, in the end, all this guy has shown is that he is a cheater, not that he is good. So, yeah... not much I can do about it. Another price of being drm-free.
On the plus side, it's about impossible to cheat during a running multiplayer game of ai war, same as with all rts games. You alter stuff on the fly, you get a desync immediately. Not that ai war is competitive in that way, anyway.