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