Each challenge is timed and when you spot the difference in the picture the time will increase but if you guess wrong the time will decrease. The interface makes it very easy to search for a match. Images slide around so you can easily photohunt. Forget other what's the difference games, this app is one of the best spot it finder apps you will play! Challenge your friends to see who can find it and get top score or just play for for fun. Also a great puzzle game for kids.