Sega has always been known for Sonic the Hedgehog but how did the Blue Blur get his speed? Well lets go back to the 80s and look at two arcade classics, Space Harrier & Afterburner.

Sega are well known for being the great innovators of the Video Game industry, many of the things we take for granted these days such as motion controls, advanced weather physics and online gameplay were just some of the things that Sega brought into gaming but one of it's first major innovations was how to speed up gameplay so we dive back into 1985 and look at Space Harrier.
There's not much to talk about with Space Harrier, you play a man who can run and fly at absurd speeds and shoot out of a large laser cannon, taking down such enemies as Cyclops Mammoths, Chinese Dragons, Blatant ripoffs of Mobile Suits and Easter Island heads. Now that's out the way, what innovations did it bring to the table? Well here's a list.
1. One of the first 16-Bit Graphic Arcade Games
2. First to use an Arcade Cabinet that allows the player to sit down and also the first to use a force feedback feature that moves in time with the player.
3. One of the first to use a Boss Rush mode
4. One of the earliest examples of a third person shooter
5. Influenced the Star Fox franchise
6. First time use of the Flight Joystick
7. And finally most importantly it brought Sega's Super Scaler technology to the forefront of games.
To explain this feature Super Scaler allowed for pseudo-3D sprite-scaling at high frame rates, with this higher frame rate it was possible to have as many as 32,000 sprites fill a moving landscape along with over 32,000 colours displayed simultaneously. In fact the games' difficulty was made all the more harder when you're moving at super speed as you avoid enemies, shots and obstacles while also trying to take them out with your own shots, so I can probably add Bullet Hell innovation to the list as well.
Two years later Sega's Top Gun style Combat Flight Simulator would take what was developed by Space Harrier and turn it up a notch as the Arcade Cabinet now rotates both horizontal and vertical to give the player the feeling of piloting the F-14 Tomcat Jet, as an extra feature there were speakers behind the player at head level that utilized stereo sound to enhance the experience.
As for the game, it's exactly the same as Space Harrier only with Fighter Jets.
Both games are legendary arcade titles that even years later are still fun to play, and in 1991 when Sonic was being made, the same technology would be used to make Sonic run fast.
This is just one of Sega's great innovations.