What is the Sonic the Hedgehog game series about

The sonic series is about a blue hedgehog who walks on two feet, talks like a cool dude, and runs at the speed of sound (named after the term supersonic). Sonic runs and bashes through levels to get to the evil Dr. Robotnik, who is a fat egghead who makes robots to get the chaos emeralds to take over the world. Sonic has to collect the chaos emeralds to stop him.
1991- First Sonic game, for Sega Mega Drive.
2006- Worst sonic game, named after original, is cursed to the Xbox 360 and PS3.
2009- Trailer for, "Project Needlemouse," new 2-D sonic game, is shown , playable in HD.