5 stars: A lot more effort has been put into the image manipulation than similar games. Some very clever psychology too. While you are looking for tiny details you miss large and obvious differences. Examine reflections. Look through windows. Make sure chairs have all their legs. Scoring is much more sophisticated too. You are timed as well as docked for wrong guesses and the use of hints. So no random poking at the screen!
5 stars: I like that this game doesn't make you race against a clock or anything. It's just a calming find the difference game. It's not all super obvious, but if you really can't find something, there's hints. And there's no animations to sit through between levels. Best of all, it's totally free, no energy to buy or hints. Just completely free.
4 stars: The pictures are pretty similar all the way through the game, going through maybe 10 different themes like buildings, rooms, table settings, etc. The puzzles are not too difficult, and the devs didn't make the game cheesily difficult with tiny little differences to spot. Because of that, each level takes between 15 seconds and 2 minutes, making this a perfect little time waster.
3 stars: Great photos used, and I like that each level has the same number of differences. One big annoyance is the length of time that the level number is in the middle of the screen right over parts of the puzzle!! There's no logical reason for this to be flashed on for so long, covering parts of the 2 photos! Please...