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) on this basic attack and two of these enhancements have become mainstays of his: the Spin Dash which was introduced in "Sonic the Hedgehog 2" and involves Sonic spinning on the spot before blasting off at full speed, and the Homing Attack, officially introduced in "Sonic Adventure", in which Sonic dashes toward a target in midair. Sonic's only weakness is that he cannot swim, sinking like a rock if plunged to a deep body of water. The only exception is that he can swim in the Sonic the Hedgehog Adventure Gamebooks. When the seven Chaos Emeralds are collected and used,