5 Differences: Find five differences between each scene. Except it's animated, and the artwork is gorgeous. And it's not so difficult as to make you tear your hair out, and not so easy as to make you feel like you're wasting your time. Not that you could feel that way, because again, the artwork is gorgeous, and staring at it would be worthwhile on its own.
This game is a joy to play. Completely. It's art and a game at the same time. It's just...I have no words. YOU HAVE TO PLAY IT, ALL OF YOU. I mean it. It's lovely.
Each level has a counter that tells you how many differences you have left to find, but the counters are integrated into the pictures, so it's different on each level. Some of them are really adorable. Watch for the phone number on the billboard. And the spinning clock. *flails*
The umbrella scene is my favorite, and not just because it features the color green prominently.
And one scene wins the award for Most Doctor Whoish. It's so sweet.
I love this game like crazy. :)