Enable the "Level select", "Super Sonic", and "Debug mode" codes and enter any stage. Get fifty rings and turn into Super Sonic. Change Sonic into the television monitor. Change Sonic back and have him jump to turn into Super Sonic. Jump on the television monitor to have Tails become invincible. Then, turn into an enemy and put it right on tails while he is invincible. Continuously place the robots there, and they will be destroyed because Tails is invincible. You should get lots of points, which add up to extra lives.