Challenge mode: To unlock Challenge mode, have a Brain Age score of 20. Slideshow mode: To unlock Slideshow mode, beat any three themes. Stamp Bonuses: Collect the following numbers of stamps to unlock the corresponding bonuses. One stamp can be earned each day that a training mini-game is completed. Note: To play the Virus Buster training mini-game, you must have earned a stamp for that day. 1 stamp - By The Numbers training mini-game 3 stamps - Stamp Design mode 5 stamps - Battle mode for Sum Totaled mini-game 7 stamps - Tips mode 10 stamps - Change Maker training mini-game 12 stamps - Virus Buster training mini-game 15 stamps - Comment Settings 17 stamps - Change Pin Tip mode 20 stamps - Triangle training mini-game 23 stamps - Calculations X 100 Hard mode 25 stamps - Multi Tasker training mini-game 28 stamps - Triangle Math Hard mode 30 stamps - Multi Tasker Hard mode