Eggmanland is the ultimate gauntlet! Now that we are almost at the end, we need the seven Chaos Emeralds! What is the best special stage to collect them?

Sonic 2 has simple and easy special stages. Heroes should have an epilepsy warning at the beginning but it doesn't.

Which would be your pick?

NOTE: Gaia Temples in Unleashed, acquiring the Emeralds via rival or boss battles in Generations, collecting the Emeralds in the world in Frontiers don't count, those are plot points. It has to be a special stage that you access at the end of the main stage.