Here is the full list of all 35 Postal III achievements.
Arrest 200 perps.
Escape from prison.
Return Thegways to the owner
Arrest eco zealots leader.
Respawn 20 times.
Euthanise 30 elderly folks.
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.
Kill/incapacitate 235 terrorists.
Finish your business with Krotchy.
Kill 1000 unarmed bystanders.
200 kills using M-60.
Spend 900 seconds or more in catnip bullet time.
50 kills using boomerang machete.
50 kills using cat.
150 kills using fire.
50 kills using bees.
Piss 100 gallons of urine.
50 badgersaw kills.
Suck up 500 items with the shop vac.
Destroy 50 cars.
Smash 50 windows.
Make Venezuela peacemakers go home.
Beat the game once. No restrictions apply. Everyone's a winner.
Taze 200 victims.
Injure yourself.
100 kills using machete in melee.
Take out all the criminal scum infesting Catharsis!
300 headshot/decap kills.
Choose path for the first time.
Disobey orders, given to you, and see what happens.