Dr. Muto

Invincibility:
Enter NECROSCI as a code. Note: This has no effect when you fall from high places.
Angel Guevara, Jr.

Invulnerable to damage:
Enter CHEATERBOY as a code.

Play as AL:
Enter CYBERDOC as a code. The message "Must I do everything myself, Doctor?" will appear to confirm correct code entry.
derrick dorsey.

Never take damage:
Enter CHEATERBOY as a code.
Angel Guevara, Jr.

All Gadgets:
Enter TINKERTOY as a code.
Angel Guevara, Jr.

Secret Morphs:
Enter LOGGLOGG as a code.
Angel Guevara, Jr.

All Morphs:
Enter EUREKA as a code.
Angel Guevara, Jr.

Go anywhere:
Enter BEAMMEUP as a code.
Angel Guevara, Jr.

View FMV sequences:
Enter HOTTICKET as a code.
Angel Guevara, Jr.

Super ending:
Enter BUZZOFF as a code.
Angel Guevara, Jr.

Pimped-up Dr. Muto:
Enter BIGDADDY as a code.

Matrix-style Dr. Muto:
Enter BLUEPILL as a code.

Chinese Dr. Muto:
Enter CHOPSUEY as a code.

Goldilocks Dr. Muto:
Enter DISTURBING as a code.

Goth girl Dr. Muto:
Enter GOTHCHICK as a code.

Jamaican Dr. Muto:
Enter GROOVYBABY as a code.

Skinless Dr. Muto:
Enter HOLLOWDOC as a code.

Musician Dr. Muto:
Enter HOTGREGMA as a code.

Dr. Muto bot:
Enter SWITCHOFF as a code.

Mariachi Dr. Muto:
Enter QUEPASA as a code.

Original Dr. Muto:
Enter RELOAD as a code.

Small character with smaller head:
Enter STIG as a code.

Mad Dog shirt character:
Enter MINISCOT as a code.

Hint: Easy Isotopes:
Zap the television in Muto's house to get 10 Isotopes.

Hint: Easy Vials:
In the junkyard, zap the dogs and vials will appear. Then, shoot them to get two more.
Mario.

Hint: Aquem: Shortcut:
On the Aquem level, there is a waterfall near the beginning. Walk through it, and you will find yourself at the end of that part of the level.
rudy ambrosi.

Hint: Junkyard: Health and producer picture:
Go to the Junkyard ending transloader. There are some pools of gook. Enable the "Invincibility" or "Never take damage" code. The car in the third pool sinks when you get on it. Once you get on it and it sinks, turn into a mouse. After the car comes back up, a picture of Bob appears along with some health bottles (not vials). Each one is worth five vials. Get the first two. Jump on Bob to get the last three.
Bilal Ayaz.

Hint: Flush the toilet:
To flush the toilet, zap it for a second until you hear a flushing noise.
Wrestle5263.