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 2 It received highly positive reviews from critics, who commended the game's level design and visuals, although its multiplayer mode was criticized. It has been rereleased on various platforms; a remastered version developed using the Retro Engine released on iOS and Android in December 2013. Two direct sequels, "Sonic the Hedgehog 3" and "Sonic & Knuckles", were released in 1994. The game's premise is similar to that of the original "Sonic the Hedgehog". Sonic's nemesis, Dr. Ivo Robotnik, is planning world domination through the power of the Chaos Emeralds and an army of robots powered by trapped animals. Specific to this