- GameBoy Advance
Retroland and Jimmy Negatron
In a rush to go to Retroland, so you can go beat up your evil double Then at the Main Menu when the ''Blue Neutron'' appear's on Jimmy's super computer, press down until Jimmy says ''Can I continue a game?'' Press A and you'll be taken to a code screen. All letters marked as B, are circled letters.
Retroland and Jimmy Negatron with full life and ammo DBD7MVGZ
This code will let you go through Retroland and fight Jimmy Negatron with 3 Jimmy Neutrons remaining, a full bar of life, and a full bar of ammo.
More Levels
At the Main Menu when the ''Blue Neutron'' appear's on Jimmy's super computer, press down until Jimmy says ''Can I continue a game?'' Press A and you'll be taken to a code screen. All letters marked as B, are circled letters.
Powerstation, My Computer, and Caves levels
NBODLHDL
Quantum Dimension, Jelly Dimmension, and Rocket Launch Site
DBYB4VHV
Select Levels
Enter the following codes to enter the levels.
JJB?X6XC9QW Level 2
5Q76J0KHX14K Level 3
?DTGYSPQRY0 Level 4
VOKC98TYL-JN Level 5
SDBH7F9MJ5J Level 6
C1MBNIL4?CC Level 7
8XY271z?8B3 Level 8