When I heard that they were considering putting handheld levels for the 3DS version of Generations I thought it was a neat idea, however, it seems that they're thrown that idea out of the window, with no sign of any handheld levels for the game. Anyway, I've decidied to list my idea of how it should've been.
EDIT: After much thought, I've decieded to change this blog to a hypothetical version of Sonic Generations that would only contain handheld levels.
- Rocket Shoes - Rocket shoes from Sonic Chaos and Sonic Triple Trouble, they'll allow Sonic fly through the air for a brief period of time.
- Strike Dash - Sonic's special move in Sonic Chaos/Triple Trouble, essentially the Super Peel Out, it will function exactly the same was as the spin dash except one must repeatidly press Triangle/Y to use
Classic era (Game Gear)
- Green Hill (Sonic the Hedgehog) - You should have Green Hill, it's the first level for crying out loud! For classic Sonic it would contain elements for the Master System/Game Gear version.
- Sleeping Egg (Sonic Chaos)
- Sunset Park (Sonic Triple Trouble) - Modern Sonic will have rail grinding section where he must jump from rail to rail to avoid trains.
- Special Stage, Fang the Sniper boss battle (Sonic Triple Trouble) - This would play like the other "rival boss battles" in the console version, Fang will ride alongside Sonic in the Marvelous Queen, and will attack by bouncing, using missiles and a drill. And possibly the oil slick ability used in Sonic Drift 2.
- Electric Egg, Egg Turkey boss battle (Sonic Chaos) - Features the second part with with the Egg-O-Matic.
- Ice Mountain (Sonic Advance) - Classic Sonic will have a snowboarding section like in Icecap Zone.
- Hot Crater (Sonic Advance 2)
- Cyber Track (Sonic Advance 3)
- Altar Emerald, Gemerl boss battle (Sonic Advance 3) - Again, this will be a "rival boss battle" Gemerl would use missiles, dash attacks and teleportations to attack.
- XX, Eggbot boss battle (Sonic Advance 2)
Modern era (DS/PSP)
- Night Carnival (Sonic Rush) - For Classic Sonic, this would contain elements of Carnival Night Zone.
- Dead Line, Blaze the Cat boss battle (Sonic Rush) - Another "rival boss battle" Blaze will use several fire attacks.
- Death Yard (Sonic Rivals)
- Hauted Ship (Sonic Rush Advanture)
- Chaotic Inferno, Ifrit boss battle (Sonic Rivals 2) - There are four main series handheld games in the modern era and only three slots available, so I figured why not?