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