I'm on the 4th map now (Berlin). The game is quite varied in its gameplay actually, and still not easy. It's a surprisingly good game in the traditional sense, although difficulty progression is a bit hard in that you have all these abilities and the game doesn't really teach them to you - you have to discover them yourself, and it takes a while to master them. From map 3 onwards, using your abilities to control the crowd, sprint and detect humans becomes pretty important. They could really have spaced the game more evenly I think, creating more levels and a smoother progression. Hopefully that doesn't get in the way of the game too much - for my wife, it would have been helpful.
Other than that though, fun game! The monster in Berlin really mixes things up - though again, I feel that it could have waited a few levels before appearing. It does make replaying levels fun though, not to mention all the VIPs and getting maximum people in record time and such. But like Elefunk, the difficulty and complexity goes up a bit too soon imho.