Sonic the Hedgehog Released in North America and Europe

Sonic the Hedgehog is a platform game developed by Sonic Team and published by Sega for the Mega Drive/Genesis system.

It is the inaugural game in Sega's flagship Sonic the Hedgehog video game series, and was the first title developed by Sonic Team. It was first released on June 23, 1991 in North America, and the same day in Europe. The Japanese Mega Drive version was released on July 26, 1991. It is sometimes retroactively referred to as Sonic the Hedgehog 1 or Sonic 1 to differentiate it from both its main character and sequels in the same series.

This game propelled the Genesis into mass popularity in North America. After it was released, it eventually replaced Altered Beast as the game bundled with the console, and was later replaced with its first sequel, Sonic the Hedgehog 2. The game featured many novel elements which contributed to its popularity and helped to promote the uptake of 16-bit consoles. The game is widely considered to be one of the greatest games of all time, placing #63 on IGN's 2007 list.

Sonic the Hedgehog added the element of speed to the standard platform formula and introduced other unique elements as well, such as the loops, springboards, high-speed devices, and the rings now permanently associated with the game series.

The game was both a critical and commercial success. As of November 19, 2007, the game has sold 4 million copies, the second-highest amount for a Genesis game, behind Sonic 2, which has sold 6 million copies.