Agreed, but you would only improve at sit-ups or push-ups, and there is a point where you will plateau. Doing push-ups 3 times a week for 10 min. won't make yo

Agreed, but you would only improve at sit-ups or push-ups, and there is a point where you will plateau. Doing push-ups 3 times a week for 10 min. won't make you good at pull-ups, which it seems is what people are expecting with these brain 'training' games. If you want to improve your mind, you do have to work it, but the work needs to be varied and consistent: work on your memory, read, learn to play a musical instrument, learn new physical skills, do math problems, etc. You have to do it all and keep doing it (unless you want to specialize, in which case you do one thing over and over as has already been said in the comments).