Chaos Angel is located on one of Angel Island's many ancient ruins which seem to have been corrupted by Dr. Eggman's experiments with Chaos Control, as a result the island's sky has become bleak and frequent thunderstorms rage in thick clouds. The interior of the ruins feature multiple pillars and what appear to be Egyptian hieroglyphics which are written on the walls.
The stage contains many dangerous hazards and traps; including rolling boulders, chambers with closing walls, and large stretches of bottomless pits with falling platforms. The level also features gimmicks similar to the Cable Cars found in Hill Top Zone, platforms which move if the player runs on them, and large, spinning bars that the player can use to fling themselves upwards or downwards, depending on which direction they are traveling in.
The third act of Chaos Angel features large platforms which the player must travel on whilst avoiding various traps and Badniks which get in their way.
Even though Altar Emerald is labeled a different zone, it can only be accessed via Chaos Angel's hub
↑Judging by the change in scenery in Altar Emerald at the end of the game, which is situated in the same location.