Endless Live:
In the main menu, press SQUARE, LEFT, SQUARE, RIGHT, CIRCLE, DOWN, CIRCLE, UP.
In the option menu you can now select the "Solo Survivor" and you will not lose
a live in 1 player-mode.

Bonus level
Enter "JODPEGEA" as a password.

Passwords:

Ziggurat:      NAEMMAAB
Backstab:     MAGDIEAH
Fall N Arch:   NINKPDME
Fugitive:       MJKKAMKC
Rainbow:      JODPIGEH
Lavapalooza: ICJABNA