I just whipped this up from Wikipedia and FAQ/Walkthrough from Gamefaqs
Gradius II: Gofer's Ambition
Returns to pilot the Vic Viper spaceship to battle the second onslaughts of the Bacterion Empire, under the new leadership of Gofer, the giant head.
Gradius II has kept the gameplay from the original game and infuses it with enhancements brought from sister game Salamander for even greater experience.
Includes all new boss rush mode, a level designed entirely with only boss confrontations.
Choose between four different weapon configurations and progressions.
The game also includes two separate types of shielding to choose from: the shield and the forcefield.
Features new mapper chip which enhances game's graphics and sounds, such as animation and even voices.
For 1 or 2 players.