The original Sonic the Hedgehog for Sega Genesis/Mega Drive first launched in Japan on 23rd June 1991 - 30 years ago today.
Sonic himself is actually a couple of years older. Like the Nintendo mascot he was engineered to replicate, Sonic first popped up elsewhere - in 1991 Sega arcade racer Rad Mobile - before getting his own game.
But it's that 1991 side-scrolling classic which defined Sonic's appeal, as well as the series' gameplay, design and villain Doctor "Eggman" Robotnik.