Here is a root structure displaying where each file should go.
.. UT2004 folder
--- System
HealthGoopGun.u
HealthGoopGun.ucl
--- Textures
HealthGoopGunT.utx
--- Help
HealthGoopGun.txt
Run UT2004, from the Mutators list you should now have Health Goop Gun Replacer as a selectable Mutator. If you are running a server make sure to add HealthGoopGun to your server packages
2. What is a Health Goop Gun?
The Health Goop Gun shoots goop very similar to bio sludge, except it has a soothing healing effect.
3. What does the mutator do?
Replaces all Bio-Rifles with Health Goop Guns and all Bio ammo with Health Goop Rifle Goop.
You can also use this weapon with other weapon replacement mutators like Arena and W.O.R.M.