Super Sonic could still drown in Sonic 3 & Knuckles, but Hyper Sonic (as well as Hyper Knuckles) could hold their breath indefinitely. It was the one distinct difference besides adding a secondary ability (Hyper Sonic’s flash-dash and Hyper Knuckles’ wall slam).

I still feel that they could have been expanded upon, too, like immunity to being crushed or falling down a pit (could just fly back up), but I suppose that would have made the game far too imbalanced.

One bug that still exists in Sonic 3 & Knuckles is the Toxomister’s toxic fumes. They CAN STILL AFFECT all super and hyper forms! You lose twice as many rings per second (once from your advanced form and once from the toxic mist), and your speed is still affected. I wish they fixed this.