I also got 650 on my last run. What I did to get that high was I mapped out my intended walkway before moving past the first square, making sure I use every move I have. Then if I lose or gain moves while in the labyrinth, I adjust accordingly. I also adjust if I see the questions ones as they pay out 30 versus the standard 10-20 points.

Also, if your getting close to running out of moves, try to avoid destiny squares if possible because it seems you tend to lose moves more frequently the closer you get to running out of them. (I know thats not system coding, its just my bad luck.)