I am no good at modding myself, but mods like this make me imagine my own themed weapon sets. I know that you might be bored with working on this mod at this point, so feel free to ignore me, but I will share my idea of a weapon set for the Going Down wad below.
Office Chair (melee)
After our hero stole this wheeled chair from the UAC offices, they took to bolting their chairs to the floor. Shame. Longer reach than the fists, but slower.
Old Faithful (pistol)
A prized possession, this high-calibre pistol is old, but well cared-for. High power and accuracy, but low fire rate.
Cell Phone Charger (chainsaw)
Allows you to use your phone for something other than receiving calls from your mother. Your phone can now be used on monsters to ring their cell phone. The ringtone annoys nearby monsters so much they will attack the target. This should not work on bosses, who probably keep their phones switched off anyway.
Office Issue Shotgun (shotgun)
Exactly why the UAC issued so many of their executives with these is a mystery. Painted white and marked with a barcode to stop executives getting too attached to them. They use shredded documents as ammo. The paper pellets hit hard, but soon fall to the ground.
Paper Cutter (super shotgun)
It's quite clear from this weapon's design that some UAC office worker has got REALLY sick of their job. Once enough paper has been stuffed into the barrel, this gun can fire it out in a deadly hail of razor-sharp shreds. Less powerful than the super shotgun, but each shred it fires can penetrate one enemy. Uses shredded documents as ammo.
Super Stapler (machine gun)
Something about the UAC office environment appears to be making the workers more and more unstable. Many of them have taken to upgrading their staplers into these rapid-fire monstrosities, firing staples with enough force to kill. Enemies put into a pain state by this weapon are briefly immobilised, stapled into place. Uses staples as ammo, of course.
Clusterf***er (rocket launcher)
The fact that the UAC would even have this weapon in their offices and labs is testament to their failing sanity. This launcher fires cluster rockets, which scatter tiny bomblets in all directions on impact.
Warp Rifle (plasma rifle)
Created in an attempt to exploit the reality-warping powers of demons, the sinister energies this weapon uses might go some way toward explaining the rapidly spreading madness. It fires a torrent of dark energy orbs which weave drunkenly through the air. The warp cells that power it have an ominous air about them, as if possessed by the souls of the hopelessly insane.
Reality Breaker (BFG)
Whether this weapon is entirely real or a product of our hero's increasingly unstable mental state is not entirely clear, but one thing is for sure - the madness is catching, not to mention deadly. Each blast from this otherworldy-looking weapon seems to be made up of a mass of disturbing hallucinations made real. The initial blast covers a wide area and any enemies that survive it either flee in terror or start to fight amongst themselves. If the BFG ammo system is set to use separate pickups, these pickups take the form of madness orbs, which seem to contain a manically laughing face that blends the features of several demons.