Complete the game with Turbo and Super versions of all characters. Then at the main menu, highlight Options, hold Y and press Start.

Go to the main menu and highlight Options, hold Z and L, enter A.

At the character selection screen, highlight Ryu and press all 3 Punch buttons and Start at the same time.

At the Dip Switch menu, change switch 28 (the switch in the 3rd row, 9th column) to 1 (enabled). At the character selection screen, hold Start and press all three kick buttons simultaneously.

At the Dip Switch menu, enable (set to 1) dip switches 27 and 28. Switch 27 is the switch in the 3rd row, 8th column. Switch 28 is the switch in the 3rd, row, 9th column. At the character selection screen, hold Start and enter Medium Punch.