Sonic runs in air
Note: You must be on Levitated Ruin and need to play get to the finish. When you get to the point where there is a Fire Soul on a rail, die and respawn. Then, go backwards to the previous checkpoint. Do not die on the way. Once you go back as far as possible, continue throughout the rest of the level. Before you get on the path, it will not be there and you will run in air.