Yu-Gi-Oh! The Sacred Cards

Yu-Gi-Oh! The Sacred Cards consists of a series of card games based on Yu-Gi-Oh!. To win each game, the player must lower his opponent's life points to zero. This is done by declaring attacks onto him using monster cards. The player loses if his own life points are reduced to zero.
In between card games, the player can walk around the city and talk to people. There are two ways to talk to people. One is to simply chat with them and the other is to challenge them to a duel. Each is done with a different button. While the game is paused, the player may re-organize their deck. The deck must contain exactly 40 cards. There are 900 cards in the game.

Source: Wikipedia, "Yu-Gi-Oh! The Sacred Cards", available under the CC-BY-SA License.