Sonic the Hedgehog platforming of the main levels. The 16-bit "Sonic the Hedgehog " consisted of a giant rotating maze, which many considered a major technical achievement. The most common special stages, however, were segments with the character running through a long tunnel to collect certain items. 3D "collect item" levels, as in "Sonic 3" and "Sonic & Knuckles", used the same perspective but had Sonic collecting all the blue-colored orbs on the surface of a giant sphere. Finally, "Sonic Advance 2" employed a 3D ring-collecting stage, and "Sonic Chaos" ("Sonic and Tails" in Japan) used a variety of gimmicks for its levels.
Sonic the Hedgehog (character) video games, Sonic's original design by Oshima was short and round, with short quills, a round body, and no visible irises. Artwork featuring this design and drawn by Akira Watanabe was displayed on the package artwork for "Sonic the Hedgehog". Sonic's proportions would change for the release of "Sonic the Hedgehog 2" on the Mega Drive; Sonic's head to height ratio was changed from 1:2 to 1:2.5. For the 1998 release of "Sonic Adventure", Sonic was redesigned by Yuji Uekawa as a character with longer legs and a less spherical body, longer and more drooping quills, and green-colored irises. For