If the guys freeze, for me it works clicking on the pause button and then resuming. However, the "congratulations" part sometimes freezes, forcing me to refresh which isn't always that fun because it doesn't count my win.
It would be nice that when you finish placing something and it's all in the right spot, that number would turn grey or something. It's really hard to keep track on what you've done and what you've placed or not.
Dear 930101, this game is an official licensed game. :)