This is what I would have gone with if I directed Sonic Generations & it probably wouldn't even have the name of Sonic Generations in the end. Modern Story would play out entirely focusing on Sonic. Dreamcast Story would try to recreate Sonic Adventure 2's feeling.
Classic Era:Green Hill, Chemical Plant, Sky Sanctuary, Diamond Dust
Dramcast Era:Emerald Coast, Radical Highway, Crazy Gadget, Seaside Hill, Egg Fleet
Modern Era:Digital Circuit, Black Comet, Kingdom Valley, Crisis City, Dragon Road, Eggmanland, Last Time
Each Story concludes with a boss that said Sonic isn't familiar with Metal Sonic Kai, Black Doom, & Egg Wyvern. This continues with Time Eater which all 3 Eras face in Last Story.
Modern Story[]
The Modern Story would be available from the start & would start off with Sonic's Birthday, only for the sky to turn a dark purple filled with lightning. Espio would say something bad's about to happen, Charmy would then get sucked in as a tornado forms from the purple clouds. Cream would get scared & run toward her mother as Vanilla, Vector, & Espio start to vanish. Blaze would rush in to try to save Cream only to get caught as well. Gemerl & Silver would try to attack the storm & get consumed as well with Silver saying "It's no use" before being taken in. Knuckles would get sucked in saying "Oh No!", Sonic would run to try to save Amy & Tails only for Amy to fade into nothing. Sonic would grab Tails hand as they both are consumed.
Sonic would awaken with Tails & notice that everything around them was white. He would ask if they were still alive only for Tails to respond that he doesn't know where they are & suggest that he try & find out with Tails pointing out Green Hill Zone which would be designed differently. With its completion Sonic would notice what looked like the purple tornado from before with Eggman welcoming Sonic to his new world. Sonic would say "What do you mean Eggman? I should have known you were behind this!" Eggman would respond "It would be better to let you find out for yourself 1st hand! There's an old friend or 2 I'm sure you're dying to see again! Maybe you should go into this purple vortex to find them?" Tails would reply "Why should we go inside? Knowing you it's going to be a trap!" Eggman would respond "If you ever want to see your girlfriend alive again I would suggest you enter it Sonic!" with Eggman then going inside it. Sonic & Tails enter to find themselves in Emerald Coast, which borrows aspects from Sonic 06's Wave Ocean.
Following this 2nd Stage, Sonic would arrive in Station Square & meet Amy who acts as though she never met them before. Amy would think Sonic was some random creep flirting with her when he tries to remind her of who he is & threaten to smash him with her Hammer much to Tails shock. Tails would ask why Amy doesn't remember them, she would reply that they never met before. Sonic would say "We get it we were too late to save you, although you're taking this pretending not to know us thing way too far!" Amy would then leave & Tails would question if Eggman did something to make her forget them.
Modern Sonic's Final Boss is Egg Wyvern.
Classic Story[]
Ivo Robotnik shows up before Classic Sonic & Classic Tails 1 day with a mysterious monster that grabs Sonic & Tails. They are taken into the future where Modern Eggman greets them by saying "It's been a few years since I last saw you both!" Classic Eggman then appears behind them & says "Or more accurately we've taken you a few years into the future where my future counterpart will hold you both prisoner so I can do the things he never could have because of you!" The duo are locked in a cage, then the Classic Robotnik goes back to his time. Modern Eggman responds "Don't worry there's no need for me to roboticize you or anything! I just need to keep you both here so that we won't have been thorns in eachother's sides!" With that Modern Eggman leaves with his monster through a portal.
About 40 minutes later Rouge the Bat infiltrates Eggman's base to steal blueprints & comes across the locked up pair choosing to free them & suggests that they use the computer to escape. Classic Sonic & Tails then enter their 1st stage Digital Circuit, which starts off like Mad Matrix aesthetically then after entering the terminal becomes like a fusion of Techno Base from Sonic Advance 2 with Digital Circuit for the rest of the stage. After completing, the pair find themselves in White Space where they encounter Shadow.
The Black Hedgehog reveals that he's searching for Chaos Emeralds in White Space & tells them not to get in his way before he enters 1 of the purple time portals. The pair follow him & end up in Radical Highway.
Classic Story's Final Boss is Metal Sonic Kai from Knuckles Chaotix.
Dreamcast Story[]
Coming Soon! Final Boss is Black Doom.
Last Story[]
All Sonics need to clear Crazy Gadget with it followed by a fight between Dreamcast Sonic & Biolizard. The 3 Sonics then need to clear Eggman Land, with it followed by a fight between Modern Sonic & Egg Dragoon. Then the player may access the Final Stage, Last Time, which has parts of it taken all throughout time. Following this the Final Boss against Time Eater begins.
Explained Story[]
Coming soon!