Brain Age is a game of mathematical equations, logic puzzles, reading exercises, and more with the curious goal of stimulating a player's gray matter. Based on the research of Japanese neurologist Ryuta Kawashima, the premise behind Brain Age is that certain regions of the brain can become more active, more "healthy," through specific, timed exercises repeated on a daily basis. Played with the touch screen positioned on either the left or right side, like a book, the game involves using the stylus to jot down numbers, draw lines between dots, and so forth, while the microphone is used for calling out colors, reading passages aloud, and various other functions.

Kawashima himself serves as the game's host and will offer pointed criticism or words of encouragement based on each test's results. The object is to make one's brain "younger" over time by playing each day for weeks or even months. Progress is charted via graph over a specified time period, with up to a year's worth of data stored in each of the game's four save files. Among the included activities are Syllable Count, Reading Aloud, Word Memory, Stroop Test, Speed Counting, Triangle Math, Connect Maze, Calculation, Head Count, and Low to High. The logic puzzle game Sudoku is also featured as a bonus, while up to 16 players can compete in a race to solve math problems.