A revolutionary platformer for the Sega Genesis that introduced the world to Sonic and established speed-based gameplay as a defining genre characteristic. Released in 1991 to compete with Nintendo's Mario franchise, it became Sega's flagship title and cultural icon.
- Developer: Sonic Team (Sega)
- Genre: Platform
- Platform: Sega Genesis/Mega Drive (1991), numerous ports and remasters
- Notable: Introduced momentum-based physics, loop-de-loops, and the iconic Green Hill Zone
- Reception: Critical and commercial success, selling over 15 million copies and spawning a massive franchise