Hard to say, since if we're going with games Shadow appeared in, that is something from Adventure 2, Heroes, 06, and Shadow the Hedgehog. Presuming its going to be than 4 levels and 2 bosses, levels are likely to be chosen from those four games; It'd be a stretch to consider anything else...
Westopolis, lol, and Radical Highway
fr Westopolis
The only appropriate scenario to put Radical Highway in Generations. Looking at you, Generations 3DS.
Yep really weird that Sonic had a Shadow level
Mad Matrix 🤪
White Acropolis
Lost Impact
Something from Secret Rings. The design and soundtrack for those stages are great, they just need a game with better controls and level design
Hard to say, since if we're going with games Shadow appeared in, that is something from Adventure 2, Heroes, 06, and Shadow the Hedgehog. Presuming its going to be than 4 levels and 2 bosses, levels are likely to be chosen from those four games; It'd be a stretch to consider anything else...
White Jungle The atmosphere of that level would just look so good in this game's style.