Here is the full list of all 35 Postal III achievements.
Kill/incapacitate 235 terrorists.
Beat game with zero kills.n(zombies and bosses don't count)
Kill no animals in one playthrough.
Complete game using only melee.
Complete game using only the pistol.
Complete Good path without falling off.
Complete game killing only males.
Euthanise 30 elderly folks.
Kill 1000 unarmed bystanders.
Piss 100 gallons of urine.
50 kills using bees.
50 kills using cat.
150 kills using fire.
Smash 50 windows.
Destroy 50 cars.
Suck up 500 items with the shop vac.
Arrest 200 perps.
Taze 200 victims.
Finish your business with Krotchy.
Escape from prison.
Spend 900 seconds or more in catnip bullet time.
Return Thegways to the owner
Respawn 20 times.
50 badgersaw kills.
200 kills using M-60.
100 kills using machete in melee.
50 kills using boomerang machete.
Make Venezuela peacemakers go home.
Beat the game once. No restrictions apply. Everyone's a winner.
Take out all the criminal scum infesting Catharsis!
300 headshot/decap kills.
Arrest eco zealots leader.
Choose path for the first time.
Disobey orders, given to you, and see what happens.
Injure yourself.