Zool 1 cheats
Type STREETLAMP at the options screen.
This gives you :
[+] (keypad) : Level up
[-] (keypad) : Level down
 : Turn on invulnerability
 : loose a life
 : Who knows ?
 : Restart level
Zool 2 cheats
Level Skip and and extra jumping height.
>From the options screen, press ESCAPE to get to the
Config Menu. Then type the word PHONEBOOK and press ESCAPE
again. Now while you're playing the game pressing 0 will
take you to the next Level and 3 will give you a bonus
stage. Also you will be able to jump higher with CTRL.