Sonic Generations (Part 1) - PC Gameplay - (2K 60fps)
Classic Sonic is running through the Green Hill until he hears a noise and senses a brief earthquake, though he ignores it. Soon after though, a mysterious entity known as the Time Eater appears in the sky and everything whites out.
In the present day in the mainstream universe, Tails arrives at a gathering that is attended by his friends. Arriving soon after, Modern Sonic discovers that his friends have been preparing a surprise birthday party for him, as it is his birthday. Modern Sonic celebrates his birthday with his friends until the Time Eater disrupts the party by sucking everyone through various Time Holes and scattering them across time and space. Not happy with this, Modern Sonic tries to attack the monster, only for it to knock him down. The impact of the attack leaves Modern Sonic unconscious in the grass.
A while later, Modern Sonic regains consciousness, though he finds himself in a strange dimension known as White Space. Noticing a colorless portion of Green Hill and Tails (now a colorless statue) nearby, Modern Sonic races through Green Hill, which regains color and life after he runs through it. At the same time, Tails is restored too. The two then spot Chemical Plant in the same colorless state as Green Hill was nearby, and Modern Sonic heads over there to investigate. Meanwhile, Classic Sonic, whom Tails mistakes for Modern Sonic, passes by and goes to Chemical Plant as well. Later, Modern Sonic meets Tails at the Chemical Plant. While there, the hedgehog tells his friend that he is getting a strange sense of déjà vu from passing through these areas. Exiting the Chemical Plant, the area goes back to normal following Modern Sonic and Classic Sonic's run through it. However, each Sonic is unaware of the other's presence. At the same time Chemical Plant is restored, Amy is restored as well.
Afterwards, the two Sonics race through Sky Sanctuary, restoring Knuckles in the process. Following that, Classic Sonic ends up on a highway in Stardust Speedway, where he defeats Classic Metal Sonic and gets a Chaos Emerald from him. Later, Modern Sonic and Classic Sonic end up inside a Boss Gate at the same time, separated by a glass wall, which they each think is a mirror. Suddenly however, Modern Eggman's voice is heard from the exit of the Boss Gate, mocking the hedgehogs and telling them that he will end Sonic soon. While Modern Sonic is unfazed by the taunt, Classic Sonic heads into the exit. Modern Sonic then realizes that there is another version of himself here, and tries to enter the exit as well, only for it to close before he is able to pass through it. Meanwhile, Classic Sonic fights Classic Eggman and his Death Egg Robot aboard the Death Egg. After the doctor is defeated though, he is kidnapped by the Time Eater as he begs Sonic for help. Later, both Sonics meet in White Space, surprised by each other's presence. They also meet both Classic Tails and Modern Tails. The four of them then discover that they are traveling through time and space, which explains the various locations they recognize. The quartet subsequently team up to stop the Time Eater's rampage and save their remaining friends.
Continuing onward, the Sonics rescue Cream the Rabbit and Cheese after restoring Speed Highway, Rouge after restoring City Escape, and Espio after restoring Seaside Hill. Along the way, the two Tailses figure out that the Time Eater is tearing space apart as it moves through time, thereby ripping places from across space and time from their locations in their timelines and placing the-now lifeless and dead areas in White Space. However, by speeding through time in these areas, the Sonics are able to fix space and return life to these areas. With the universe about to fall into chaos because of the Time Eater however, the Sonics realize they have to get going like never before. Soon after, Modern Sonic claims a Chaos Emerald following a meeting and clash with Shadow onboard the Space Colony ARK. Not long after, he finds himself in a flooded Station Square where he defeats Perfect Chaos. Afterward, the Classic and Modern pairs discover that the Time Eater does not like the Chaos Emeralds, making their hunt for the gems even more important. Continuing their adventure, the Sonics pass through Crisis City, Rooftop Run and Planet Wisp, restoring these locations and rescuing Blaze, Vector and Charmy too. Meanwhile, Modern Sonic wins a Chaos Emerald from Silver after defeating him in a fight in Crisis City. He also goes on to fight Modern Eggman and his Egg Dragoon in Eggmanland. After defeating Modern Eggman however, the doctor is taken away by the Time Eater, confusing the heroes.