are unlocked: Quick Play, Daily Training, and Sudoku. In Quick Play, the player can practice with any of the available minigames without receiving a score. In Daily Training, the player can perform Brain Age Check to determine their updated brain age. They can also complete one of the available minigames, after which they are given a rating based on their performance. In Daily Training, the player can also play Virus Buster, a simplified version of Dr. Mario (1990) modified for mobile play. Note that the background music for Virus Buster alternates every day between the "Chill" and "Fever" themes. To let the player track their progress, the game saves daily statistics of the player's performance, which are shown in a graph. In the third mode, Sudoku, the player can solve one of a hundred Sudoku puzzles. All of the minigames in Brain Age 2 are different from those of the original Brain Age. Brain Age 2 contains six minigames: Rock, Paper, Scissors, Serial Subtraction, Symbol Match, Math Recall, Number Memory, and High Number. The game's Training mode includes the following activities: Sign Finder, Piano Player, Word Blend, Word Scramble, Change Maker, Calendar Count, Memory Sprint, Math Recall, Clock Spin, and Block Count. During their training, the player can collect stamps by completing minigames, and only one stamp can be collected per day. When a certain numbers of stamps are collected, new minigames and features are unlocked. Development At a Nintendo press conference in Tokyo, Japan on October 5, 2005, the company announced several games that it would be releasing in 2006 in Japan. The list included Brain Age 2, with a release date set for December 29, 2005. Nintendo later announced that the game would be released in Europe on June 29, 2007 for €30, and in Australia on July 5, 2007 for A$49.95. The American version of Brain Age 2 was first revealed in May 2007. The game is targeted to casual gamers, similar to its predecessor; its basic concepts stay the same as in Brain Age, along with the graphics, menu, and presentation. Brain Age 2 also uses the same Sudoku engine, an addition in the original Brain Age that has been applauded for being one of the best handheld Sudoku games available; Brain Age 2s rendition of Sudoku introduces 100 new puzzles. All of the minigames in the game are new to the series; however, some of