After his last defeat, Doctor Eggman is abandoned in outer space with his robot henchmen Orbot and Cubot. An enigmatic time-travelling thing known as the Time Eater appears. Realizing its potential, Eggman uses its ability to go back in time and team up with his past self. The two convert it into a robot to obliterate their past failures from history. The Time Eater flows to strike Classic Sonic as he tours Green Hill at the birth of the original Sonic the Hedgehog and interrupts a birthday celebration being held for the present Sonic by his companions, spreading them all through different time portals. Present Sonic wakens in White Space and saves Tails after spanning through Green Hill. Modern Sonic and Tails finally meet their Classic doppelgangers and ally to restore their world. Sonic Lovers can hop in and try out more sequels on this Game:

• Sonic Generations 
• Sonic Generations Collections
• Sonic Adventure Dx 
• Sonic Adventure 2 
• Sonic 3d Blast
• Sonic & All-stars Racing Transformed 
• Sonic & Sega All-stars Racing 
• Sonic the Hedgehog 2
• Sonic Spinball
• Sonic CD

Key Features 

• A giant purple monster steals all of the sonic friends and dumps him into a limbo where he meets his past self. To restore time and space, sonic has to relive moments from their past and run fast because that fixes time somehow. 
• The Game is entirely a homage to the franchise, full of jokes, familiar locales, and characters.
• Everything in Sonic generations looks good while you're in motion; like a racing Game, it's designed to be sped past quickly.
• Every significant stage in Sonic generations has two acts: Classic side-scrolling sonic and modern 3D homing attack sonic.
• The old school's platforming and the more modern, almost racing games levels fit together nicely though there are still the occasional moments of clunky controls that can stop the action dead.
• Every Level is a recreation of a story from a previous Game. It's what makes this whole Game so fantastic.
• There are boss battles. Players will fight familiar bosses and rivals like perfect chaos and metal sonic.
• There are also challenge missions that mix up the gameplay, which is optional.
• The Game's central hub is a kingdom called White Space, where the player can explore, chat with other characters, and access the Game's levels, each of which emanated from a last entry in the sequel.
• In Sonic, generation levels are divided into three individual eras; the Classic Era, the Dreamcast Era and the Modern. Individually, Level consists of two acts, one for each Sonic and ten extra assignments, such as gathering a certain amount of rings or finishing a Level with the help of another ally.