Level select:
Hold 1 + 2 + Start and continuously sweep the D-pad when Tails begins to run in the opening sequence. The sound of a credit being added will confirm correct code entry. Press Start to continue.

Bonus life:
After completing a level with less than 50 rings, run through the turnstile. Stop and jump into the air. Timed correctly, the turnstile should stop spinning while it is off the screen and display an extra life power-up when Sonic lands.