Enter the following two codes after defeating the first boss. The
number of times each code can be used directly corresponds to the number of
Double shot power-up:
Up, Up, Down, Down, Left, Right, Left, Right, L2, R2
Laser shot power-up:
Up, Up, Down, Down, Left, Right, Left, Right, L1, R1
Free play mode:
Play for 18 hours.
Weapon edit mode:
Beat the game, then go to the weapon selection screen and press R1.
Press L1 to exit.
Thanks to Revolution readers Wind Jammer, Russel and Fire Kabong!