Unlock Pro Difficulty
Beat the game once to unlock hard difficulty. Beat the game on hard difficulty to unlock Pro difficulty.
Level Select
At the startup screen, hold [R] and press [Up]x9 times. You'll hear a tone. Then, start a game, pause it, hold [R]+[A]+[Select]. A level number will appear in the lower left corner. Use Up and Down to change the number, then unpause your game to warp to that level.
Power-Ups
Press [Down], [R], [Right], [Down], [Right], [Right], [Down], [Right], [Down], [Down] on the title screen. A tone will sound. Next, start a game and pause it, then press [R], [Right], [Down], [Y], [Down], [Right], [Down], [Left], [Right], [Down], [Right], [Right].
To select your power up, press one button from the list below to choose your initial attack, then press another button to choose missiles or bombs.
[A] - Sky Laser
[B] - Ground Laser
[X] - Reflect Laser
[Y] - Spread Laser
[R] - ShotGun Bomb
[A] - Homing Missiles
[X] - Spread Bomb