In the train stage, go to the room where a flying robot and a man with a flamethrower are, beat them, then go to the platform where the man was, press up on the D-Pad And a blue butterfly will appear in the screen, worth 1000 points.
Enable Widescreen Display
You can change between regular and widescreen display modes at any point in the game. Press the L and R buttons at the same time to toggle the display.