A fixed target — six differences, no more, no fewer — which changes the game more than it sounds like it should. Knowing the number means you can tell when you are done searching and when you have missed something.

The images are clean and the differences are genuine rather than pixel-hunting. Later levels use busier scenes where a changed object hides among similar ones.

When you have five and cannot find the sixth, it is almost always in the background rather than the subject. Sky, walls, floor patterns — the areas your eye skips because nothing is happening there.

Straightforward, well made and appropriate for any age.