In order to show more progress for leveling than the standard game there are a few bonuses per level that are not part of the normal TMNT system. You will gain skills and BIO-E points at regular intervals to show you are improving and growing stronger. BIO-E points can be used to further your mutation, give you more human features or add animal powers. There is also the option to expand your Psionics if you started with them or take a list of minor super powers on the Additional Powers Page.