More ideas:
* The Sonic collection would be a hybrid between Super Mario All-Stars and Rare Replay: half remakes, half comprehensive collection.
Cart 1: The Classic Era
(In general, all characters are playable in all games, but some must be unlocked in one game before they can be used in the others. There are also HD graphics now, and redone soundtracks)
* Sonic 1 (hybrid of 8 and 16-bit stages, with revamped level order and original order. Redone order is Green Hill-Bridge-Star Light-Spring Yard-Jungle-Marble-Labyrinth-Scrap Brain-Sky Base-Final. Possibly also some previously deleted stages from concept art or the unreleased Amiga version?)
* Sonic 2 (includes all the deleted stages, as well as branching paths. Paths diverge starting at Aquatic Ruin, where you can go to either Casino Night or Wood Zone. And then they branch again at Hill Top. One path leads to Dust Hill, the other to Mystic Cave. Mystic Cave route continues mostly like the final game, but Dust Hill follows with Winter Zone and then another branching path to either Rock Zone or Green Hill. Mystic Cave has an alternate path to Hidden Palace which is followed by Green Hill. Bionic Sonic from the 8-bit game is the boss of Green Hill. Ashura is now a proper hidden character with his own abilities, who is unlocked with that old trick to get him.)
* Sonic 3 (Combination of S3 and S&K. Different characters have different level orders.The multiplayer stages also occur in single-player campaigns now. Mecha Sonic and Egg Robo can be obtained by getting all Super Emeralds.)
* Sonic CD (Desert Dazzle and Final Fever added. Amy and Metal Sonic can be unlocked via getting the time stones early using these two Rounds. Also, level designs are revamped. SEGA logo resembles the one in SEGA Classics 3-in-1, but with the SEGA Jingle)
* Knuckles Chaotix (Revamped level designs and a few new bosses. Possible homages to adaptations/the un-materialized Sonic Mars and Crackers? Wechidna is now a proper playable character with his own abilities, unlocked with that old trick to get him. And the SEGA screen now has the jingle play, and the psychedelic backdrop is layered over the island map)
* Sonic Triple Trouble (Includes some stages from Sonic Chaos. Nack is unlocked by clearing all special stages with him in it. Knuckles has a campaign with a mix of stages from this and Chaos. Maybe also some Sonic Blast content?)
* Sonic Spinball (Primarily based on Genesis version, but has some bosses from the GG version re-purposed as mid-bosses, plus stages taken from the early version by STI. Sonic's more familiar Jump sound is used instead of this game's one. Sally and Bunnie are unlockable via clearing the game.)
* Sonic 3D Blast (Full 3D-rendered environment now, largely based on Saturn Version with Genesis special stages repurposed as Bonus Stages that give power ups or instantly free Flickies.)
*Unlockable, unchanged entries: Sonic R, Sonic Chaos, Sonic Blast, Sonic Labyrinth, Dr. Robotnik's Mean Bean Machine, Sonic Eraser, SEGASonic Arcade, Sonic the Fighters, Sonic Pocket Adventure
Cart 2: Dreamcast/GC era
* Sonic Adventure
* Sonic Adventure 2
* Sonic Heroes
* Shadow the Hedgehog
* Sonic the Hedgehog 2006
Unlockable: Sonic Advance, Sonic Advance 2, Sonic Advance 3, Sonic Rush, Sonic Rush Adventure, Sonic Rivals, Sonic Rivals 2, Sonic Riders
Other games:
* Freedom Planet 3
* Earthworm Jim: Menace 2 the Galaxy Remake
* Earthworm Jim 4
* Mortal Kombat 9 & X compilation (possible inclusion of Injustice)
