Sonic Mania 2: Emerald Escapade

Sonic Mania 2: Emerald Escapade is an upcoming Sonic Mania sequel which is going to be released in 2028 by Sega and developed by Christian Whitehead, Headcannon, Hyperkinetic, and PagodaWest Games (The same team as Sonic Mania. 

Plot
This takes place after the ending of Sonic Mania Plus, where Classic Sonic goes up against a new foe, Metal Sonic. Metal Sonic has the Phantom Ruby and the Chaos Emeralds, meanwhile, because of Knuckles being possessed by Metal Sonic, there are now duplicates of Tails, Knuckles, and Amy in Metal's form....under Infinite and Metal Sonic's control, to also get the Master Emerald and rule the world, and overthrow Robotnik, once and for all....

Zones

 * 1) Green Hill Zone
 * 2) Chemical Plant Zone
 * 3) Sky Sanctuary Zone
 * 4) City Escape Zone
 * 5) Metallic Madness Zone
 * 6) Green Hills Zone
 * 7) Super Sonic Warrior Zone
 * 8) Super Sonic Battle Zone
 * 9) Cosmic Eternity Zone