Sonic Generations is a game about when Sonic's friends were celebrating Sonic's 20th birthday and the Time Eater came and sent Sonic's friends into different zones that Sonic already passed and on the journey,Sonic meets Classic Sonic and Tail's meets Classic Tail's and then the both Sonic's have to free his friends,find all 7 Chaos Emeralds and defeat Dr.Eggman and Dr.Ivo Robotnik to save the day and celebrate the rest of Sonic's birthday.

sonic_(series)
sonic_the_hedgehog
miles_prower
blaze_the_cat
shadow_the_hedgehog
metal_sonic
knuckles_the_echidna
marine_the_raccoon