Easy mode
Press [X], [B], [Y], [A] four times at the title screen. The phrase "Easy game" will be spoken to confirm correct code entry. Your weapons will charge faster than normal. Alternately, press [X], [B], [Y], [A], [X], [B], [Y], [A], [X], [B], [Y], [A], [X], [B], [Y] at the title screen.