At the title screen, after the animation ends (when you can see “Operation C” completely), enter this code. Up, Up, Down, Down, Left, Right, Left, Right, A, B, A, B, Start. If done correctly you’ll hear hear a chime and a “Stage Select” box will move in from the right side of the screen. Press down until you can select Stage 4. There are actually 5 stages but there isn’t much left from this point. Make sure to grab the two Spread Gun powerups in Stage 4 to make the rest of the game as easy as possible.