This is a pretty fun game when it comes to playing with friends, as it's an overall competition between the people and the dog most of the time (even though that's not the point of the game.) It's interesting to play with the piggy back mechanic and how the gravity for them works.
From what I can tell, the dog perhaps, would be nice to add an interesting function to them aside from being able to push things, as all they do is go forward or jump. Perhaps a similar step mechanic? I'm not sure, but otherwise, pretty cool game.