2/3 of them are references to

Sonic's Concept and is also a Skin in Sonic Superstars Cream's Debut (Though inconsistent looks)

A former 90s rival's (A red capped plumber guy) recent 3D platformer since 2017

(Advance 1) Angel Island Zone.

Originally for Infinite Battle Now retooled

Basically

Valgallah's Cream's "Chao Force" Super

Command is

D,DF,F X+Y

Despite being Water (Or Mutated Chao) slime sounds

I'm taking you down like its 1998/1999!

Giving the character's Icons some polish.

(Will be in the next update)

The "Big Green Man" (Guest) teaser.

Act Music as Rounds? (may not apply to every stage)

Sumin didnt just make some characters But also sandbag (Though bare bones)

(Silver Update)

Another Trap attack + A returning move from Infinite Battle + And another intro