Sonic Advance 3: Part 30: Special Stage 1 (Red Chaos Emerald)
11After gathering all 10 Chao in Zone, between all 3 of its normal Acts and (with one exception) the Zone's map field, you can then go on to collect a Special Key from an Act. You have to beat the Act in order to keep it, and you can only get one at a time.
Bring the Special Key to a Special Spring hidden somewhere in the Zone's map in order to final reach the Special Stage.
----------
In a Special Stage, your character will right on top of Tails' Tornado 2. Use both the plane and your character so that the character collects Rings along the way.
You will go through two rounds of collecting enough Rings in order to advance. Beat both of these rounds to a get a Chaos Emerald. Fail once, and you'll be booted out and will have to bring another Special Key to try again.
Along the way of these Special Stages, you will find some hazards that will knock Rings out of you. There will also be some helpful stuff, like a Super Ring that's worth 5 Rings, and Ring Boosters that transform the Tornado 2 to make it faster, but also doubles the Rings you collect. Combine this with the Super Ring, and that can give you up to 10 Rings.
----------
This first red Special Stage is found in Route 99's Map. It's a fairly simple one with very VERY little hazards to dodge.
Since I didn't take the time to get a Special Ring out of this Zone, I had to go back and find one before starting this.
This Special Stage will need you to collect 80 Rings for Round 1, and then 160 for Round 2 before it gives you the Red Chaos Emerald.