Based on the master Sega Genesis version, Sonic The Hedgehog was recreated as the number one Sonic game for the Sega Master System. Not just a straight port, this variant features new levels, bosses, some unique geographical zones and an areas map. The most detectable difference, however, is that the Chaos Emeralds have to be recovered inside certain phases other than the Special Stages. Dash along six Zones (including extraordinary zones that were only accessible for the Sega Master System version) and face Dr. Eggman (a.k.a. Dr. Robotnik) at the end of all areas.