Touchdown Fever (NES)
Touchdown Fever is one of the many, many American football games on the NES.
On the formation selection screen hold Select on Controller 1 and press B on Controller 2. The number next to "FORMATION" text will be displayed representing current formation internal index. While holding Select press B on Controller 2 again to toggle this index off.
Complete the game in Tournament mode. When the staff roll has ended, on the "PRESENTED BY KAC" screen press Up, Down, A, B, Left, Right, B, A, Select, Start. There won't be any changes on the screen nor any activity display. But if you press some buttons, the effect will follow: Up or Down select a music track, A and B will start or stop the song, respectively.