A good game to start with, but your interest shall slide.
The DS is turned on its side much like a book and has you writing your answers on the touch screen, tapping the correct answers or speaking into the microphone. The games consist of a variety of things. One game titled Calculations x20 (in which you can unlock other, harder versions) sees you quickly answering mathematical questions as quickly as possible. Other games are - but not limited to - things such as keeping track of how many people stay in the house, saying aloud the colour of the word and not the actual word (for example, the word could be coloured red but the actual written word could be green), tapping numbers from highest to lowest and memorising words (easily the most boring game). After this the game then calculates your brain age.
There is also multiplayer (not Wi-Fi, though) mode which let you play the calculation game against up to 15 other players solely using your cartridge. There is also a side game of Sudoku which has a large amount of puzzles to complete. The Sudoku is actually set out very nicely and uses the touch screen to its full use.
The downside of this game is that of the speech and writing recognition. You may write your 9s differently to how the game wants you to write it or you may quickly scribble down an answer and have the game drop marks for thinking you wrote the wrong answer. The speech recognition is also poor in some places as when you clearly say the correct answer it'll tell you you're wrong, making you waste time having to repeat yourself.
A small downside is the fact this game is quite serious and you won’t particularly find any humour in here (except Dr Kawashima's quite frankly awful jokes) and if you are looking for a similar, fun but more light-hearted game, you'd be better off with Big Brain Academy. Overall, a solid low budget game.