Brain Age 2 review at 1-up.

"That wacky brain doctor is back with 17 new mental minigames in Brain Age 2, and whether you're doling out dimes, quarters, and nickels or counting a runner's ever-changing place in a footrace, they all provide a nice intellectual workout -- much more so than the original. In this way, it's a big improvement; few of these struck me as too easy, and it's now harder to quickly ace the tests and rocket right up to the ideal brain age of 20. I vastly prefer Rock Paper Scissors, where you have to call out the winning (or losing) move in the game, to the original game that had you calling out the color you saw on a screen. And Serial Subtraction, in which you subtract a particular number over and over again, also felt like it was genuinely challenging my brain instead of the original's too-basic arithmetic."

Full Source: 1-up