It’s a good game mechanic, but it’s the wrong one for Rovio’s 2nd big title. Puzzle games just aren’t as sticky on mobile (fast pick up and play) as twitch games. It might be a great game and the few who play it might love it… but for the majority of people, the engagement times are going to be far lower, frequency of play will be lower, and it will be labelled a failure. I am happy that Rovio is moving beyond Angry Birds, though.. I think that license is quickly becoming stale.