Teddy Boy

Extra options:
Press Up, Down, Left, Right at the title screen. "Continue", "Fire", and "1-P" options will appear.

Level select:

Enable the "Extra options" code. Press Up, Down nine times, 1 at the extra options screen. The word "Round" and a number will appear at the bottom of the screen. Press Left or Right to select a new starting level, from 1 to 50. Press 1 to begin game play at the selected level.

출처 : http://www.gamewinners.com/SMS/TeddyBoy.htm