things you should add:
super cancel (press c again when transformed to cancel the transformation) it will be cool to add that cause you will have more control of the super transformation and you can transform and cancel the transformations when you will want.
tails flight cancel (press down+a b or c when flying with tails to cancel the flight) it will be cool to add the flight cancel cause i'm now familiarized with the flight cancel from sonic 3 air and it will have more control of the tails flight.
drop dash (sonic only) a b or c when in mid air to do an instant spindash. it will be cool to add the drop dash as an extra option to sonic in the extra menu.
things you should fix:
the charge time of the super peel out.
the extremely loud sound of the point counting in the results screen of a special stage (i've did a comment about that. but anyways, i've will add it.)
change the invincibility theme of sonic & knuckles to the invincibility theme of sonic 3d blast.
the crush hitbox in gene gadget zone.