Concentration is played by one player. Open two cards at a time, and if they are both the same number they are removed. If they are different numbers then the cards are returned to being face-down. Remove all the cards as fast as you can and try to beat the high score! Compatible with all iDevices: iPhone, iPod Touch, and, of course, iPad! Compare your clear time with people around the world using Gamecenter's score system! Great for those who: ・ love games of patience such as Solitaire, Klondike, FreeCell, Spider Solitaire ・ are looking to kill some time between bus and train rides on the way to and from work or school ・ enjoy a good puzzle ・ are interested in other card games, such as Poker, Blackjack, and the Japanese Daifugo ・ enjoy other board games such as Reversi, Othello, Crosswords, Chess, and the Japanese Shogi and Go No need to register your email address! This app is a free download.