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