Sky Road: Zone 4
Red Star Ring 1: This one is found at the top of a zigzagging line of rings just above the starting point.
Red Star Ring 2: When you're sliding down the sandy chute, not long after weaving past some spiky balls, a number of centipede-like enemies will begin emerging. You'll find the next Red Star Ring between two groups of them.
Red Star Ring 3: During the reverse-camera sliding sequence, after you shimmy across the first black-and-yellow railing, you'll be chased by a rolling cactus. The Red Star Ring will appear on the right side of it, moving towards you from behind.
Red Star Ring 4: After finishing the second sliding sequence, you'll land in another side-scrolling sequence. A short distance upward, you'll come to a couple of platforms that Sonic can move by bouncing on them. Between them is a bell. Chase it quickly up the collapsing structure and to a remote platform on the far-left side of the area. This will reveal a Red Star Ring in the center.
Red Star Ring 5: Shortly after you pass the second checkpoint of the same area and begin avoiding the large ghosts, you'll find the final Red Star Ring tucked away in a small alcove on the left.