This 3x3 sliding puzzle could use some extra mechanic, maybe via special characters/tiles? here are a few ideas
- a guy that cannot be shifted into a certain square or you lose
- another that rotates its neighbors when being shifted
- one that when swapped takes the control from your original character until you swap back with it
- tiles that only let you enter one way could be used to make more unique levels
I felt scoring was a bit unfair/pointless here as it is more about getting a less shuffled level to begin with than your solving skills. For this reason, I think scoring and limiting moves in this sort of randomized puzzle may not be a good fit.