More on both of these areas are on the Skills & Collectibles page.
Now that you're free to move around, you might want to head left of Green Hill Zone and check out the Skill Shop and the Collection Room. Tails will unknowingly talk to Classic Sonic before you're allowed to continue your journey in the White Space. Tails won't find Green Hill Zone familiar (after all, his debut game was the one after Sonic 1. Once you're back in the white void, Tails will be freed from his statue-state. Defeating enemies and collecting rings will slowly refill your meter, so if you feel like you might run out, look around for a quick pickup. Boost whenever you can to crash through enemies and gain tremendous momentum, but keep an eye on your boost meter. With this different play style, you'll spend a good chunk of the level facing Sonic's back instead of his side. Once you're ready, head to the white structure in the middle of the small amount of space you can move in to play the next level. You can test out two of Modern Sonic's moves now: jump after being in midair to do a homing attack, introduced in Sonic Adventure, and hold to do a boost, from Sonic Unleashed. This is the hub world of the game, where you'll be able to access every Act, Challenge Act, and Boss Battle in the game. The Time Eater knocks Sonic back before he can get close, and wakes up in a white void after passing out. It isn't too long before everyone at the party is also sucked up by this villain. After this, Modern Sonic is treated to a birthday party, where Tails presents him with a chili dog, his favorite food.
This is the only stage in which this can happen, and it was also possible in the original Chemical Plant Zone. In Chemical Plant Zone Act 1, Sonic can sometimes outrun the screen.One of them dances exactly like Yacker dances on the Loading Screen of Sonic Colors. White Wisps can be seen in the beginning of Planet Wisp.One of the streets in Speed Highway is named 123 Omega Road, referencing E-123 Omega.In City Escape, Bark the Polar Bear, Fang the Sniper (aka Nack the Weasel), and Bean the Dynamite appear on "Wanted" posters, and Mighty the Armadillo and Ray the Flying Squirrel appear on posters reading "Missing since 1993" 1993 being the year SegaSonic the Hedgehog came out, which was Mighty and Ray's debut (and Ray's only appearance as a playable character by that point he didn't return until Sonic Mania).This is possibly a reference to the educational game Sonic's Schoolhouse, in which Eggman appeared as a teacher. In The Stinger, Classic Eggman mentions that he's thinking about getting a teaching degree.Sonic mentions to Tails that their current adventure is "no stranger than rescuing genies from magic storybooks or saving aliens in an interstellar amusement park", referencing Sonic and the Secret Rings and Sonic Colors respectively.This is possibly a reference to Sonic Riders, in which Eggman did win, but all he got was a carpet. In The Stinger, Classic Eggman asks Modern Eggman if they ever win, to which Modern Eggman replies that it depends how you define "win".Robotnik!", to which Classic Eggman replies "Nobody calls me that anymore." After Classic Eggman reveals himself, Tails exclaims "Dr.
People who played Sonic the Hedgehog 2 will likely agree with him, due to an infamous section in act 2 where the water rises, forcing Sonic and Tails to constantly jump up moving platforms to avoid drowning.