In case anyone's interested, I went from a Lumia 925 with the Insider Preview of 10, did a backup, restored it on a new Lumia 640 with official 10 installed and all that was restored from that backup was the actual apps but not a single one of the saves or user data. Don't know why. I tried several experiments, taking the 925 off insider preview then backing up, backing up only some of the apps to see if it was choking on doing too many, and I could never get it to work.
So, I've lost an enormous amount of game saves but I've had enough of hard resetting. I just wanna enjoy my 640. If anyone has any input into why the saves wouldn't come back or can think of something I could try I'd really appreciate it.