Whack a Difference 

Whack a Difference is a simple game, in which users need to identify the object that differs from the rest ones they are presented with. The objects may have different shapes, different filling color, border, and so on. There will appear three pictures (mainly stars, numbers, circles, rectangles, etc.) on the game's window and users should quickly identify the odd one out. In order to score a great amount of points and appear in the highscores table, the players need to react quickly and be concentrated, the faster they choose the correct answer the more points they gain.

As you can see, the rules are very simple and the game doesn't look challenging at all, but when you continue playing you realize how 'blind' sometimes you may be, not seeing the difference between the objects at all; or you may click on another object by impulse.

All in all, this game is too simple: it is really short, since it only consists of 20 questions. It features a simple, not very attractive, though bright user interface and suitable sounds, but no music, and, as you already could have guessed , no customizable options. However, you may play this game to fill your time.