Could these be spindash animations?
Sonic "floating". His shoes are completely red as well.
The green hill wrecking ball.
Star light Zone unused lights.
Missing machine parts....
"need air"
Exploding robotnik sprites
sideways spikes
Totem poles
Falling/shrinking sprites
Standing air spite
Sliding sprites?
End victory pose
A horizontal Burrobot
The back of Robotnik's Legs. This can't be viewed in normal gameplay