Thing is, even though batteries are SUPPOSED to be dead by now, every single one of my old NES games with a save feature still work fine. This is a rather weird problem, but yeah I suppose it would be best to try a new battery. Actually I happen to have a few of the type they are supposed to use. I've heard soldering is involved, but the pics I've seen just show the battery as clipped in there rather than soldered. I'll find out when I open it up I guess. At any rate I'll need to order that special bit in order to get the thing open. If I can't get it working, I'll either sell it outright or trade it in somewhere for a copy that doesn't have this error.