NeuroNation training is always tailored to your personal individual performance.
This means that you stay adequately challenged but not overwhelmed by the difficulty of the exercises which you are training with. As a result, you should see constant improvement and stay motivated. Not only does the level of difficulty increase as you progress, but also the time which you have to complete exercises decreases the more you train.
You can compare your progress to the performance of other members as well - your initial performance, and your progress.