Can be frustrating, but for $20, it's a bargain.
When you start up the game, it makes you take the test. The first game is the stroop test. The stroop test is when there are colored words and you say the color of the word, not the word itself. You'll immediatly notice it can't understand you when you say blue, making the test near impossible to beat. However, if you say...higleiahai or some other gibberish, there is a 25% chance it'll work. When your done you'll play a math game. The math games work much better, but are still really hard to beat, because it can't always read your numbers. Most other games work well, but since these are major tests, it can take away from the game. You unlock new games over every few days, but there are only a few to unlock, so it gets boring after a while. You have to play at least 3 games a day, and it doesn't matter what game you choose, or in what order. There really aren't any amazing graphics, mostly just numbers and letters written down. There is a sudoku game with tons of levels, and it teaches you how to play. It's addicting as hoola baloo!
In short, for $20 it's worth it, but expect flaws.