This code only works for Sonic. First, do the Level Select cheat. In the Level Select menu, go to Sound Test and hear the sounds 04, 01, 02, 06 in this order. If done correctly, you'll hear a Chao Emerald sound effect. Now, select any stage from this menu and not only you'll be able to turn into Super Sonic with 50 rings but also you'll get Sonic's second ending after beating Death Egg Zone.