Once you unlock the original PD from the appendix of Pandora's Box, you can use the codes below:

At the title screen of Panzer Dragoon (the original) press UP, UP, UP, DOWN, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT, LEFT, RIGHT, L, R. Now you'll have to shoot enemies to regain health

At the title screen of the original: L, L, R, R, UP, DOWN, LEFT, RIGHT

At the title screen of the original: UP, UP, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT, X, Y, WHITE

At the title screen of the original: L, R, L, R, UP, DOWN, UP, DOWN, LEFT, RIGHT. The game will be twice as fast in Wizard mode.