Circles is very simple. It's a memory game. You start with between two and six hollow circles on the screen. The circles will light up in a sequence and you have to tap the circles to recreate the sequence. After each successful completion the sequence repeats and adds another one at the end.  The game has a series of levels, each with one more circle than the last (from two to six). Complete sixteen rounds of the sequence and you unlock the next level. The last couple levels have lightning bolts and other odd symbols next to them instead of the number of circles, and I'm not sure what's up with that since I didn't unlock that far. But hopefully those levels add some variety to the proceedings; things are a little dry as they are. (There IS a multiplayer for anybody with Game Center friends but I was not able to try it out.) Still, there's nothing wrong with a simple game and if you like testing your memory or are trying to prevent Alzheimer's, this is as good a game as any to try out.