Aero Fighters

Play as Rabio:
Hold R and press Left, Down, Right, X, Y, A, B, Left, Down, Right, Down, X, Y, A, B on controller one at the character selection screen.

Play as Lepus:
Hold R and press Left, Down, Right, X, Y, A, B, Left, Down, Right, Down, X, Y, A, B on controller two at the character selection screen.

Boss endurance mode:
Hold R and press A, Left, Y, Right, X, Down, B, Up on controller two at the character selection screen.

Super Hard difficulty:
Hold R on controller one and press Up, Left, Down, Right, B, A, X, Y on controller two. A sound will confirm correct code entry. Select the "Super Mode" option at the title screen.