Cheats
Description
Earned by
Laser sight ammo
Lets you add the Laser sight utility to your setups.

Complete mission 4

Jetpack ammo
Lets you add the Jetpack utility to your setups

Complete mission 8
Fast walk ammo
Lets you add the Fast walk utility to your setups

Complete mission 13
Invisibility ammo
Lets you add the Invisibility utility to your setups

Complete mission 16
Low gravity ammo
Lets you add the LowGrav utility to your setups

Complete mission 20
Banana upgrade
Upgrades the Banana bomb to become more powerful

Complete mission 33 (final mission)
Super sheep -> Aqua sheep
All Super Sheep become Aqua Sheep (will swim underwater)

Gold on Sheep Racing
Longbow upgrade
Upgrades the Longbow to become more powerful

Gold on Euthanasia
Enhanced shotgun
Upgrades the Shotgun to become more powerful

Gold on Rifle Range
Enhanced grenades
Upgrades Grenades to become more powerful

Gold on Artillery Range
Blood
Makes the worms bleeeed

Gold on Basic Training
Indestructible landscape
Weapons won't destroy the terrain

Complete mission 25
Invincible worms

Worms won't die (unless they drown)

Elite on Deathmatch
All crates are sheep
All crates contain sheep

Gold on Crazy Crates
The Full Wormage
A (non-editable)* setup with all weapons, at full power.

Complete all missions, training, and deathmatch.
* By non-editable, we mean that if you edit the setup you will lose the enabling of all the secret weapons.
These are taken from:
http://www.worms.team17.com/pc/?cheats