Press Down, Down, Up, Up, Left, Right, Left, Right, 1, 2, Start at the
title screen to enable cheat mode and a sound test option.
Press Up, Up, Down, Down, Right, Left, Right, Left, Start at the title
Press Up, Down, Up, Down, 1, 2, 1, 2, 1, 2 at the Sonic/Tails selection
screen to automatically receive an emerald during level 1.
Press Up + 1 or Up + 2.
Enable cheat mode. Press Down, Down/Right, Right, 1 during game play
to shoot fireballs.