Here is the full list of all 35 Postal III achievements.
Suck up 500 items with the shop vac.
100 kills using machete in melee.
Smash 50 windows.
200 kills using M-60.
300 headshot/decap kills.
Destroy 50 cars.
50 kills using boomerang machete.
Finish your business with Krotchy.
Escape from prison.
Injure yourself.
50 badgersaw kills.
Beat game with zero kills.n(zombies and bosses don't count)
Kill no animals in one playthrough.
Complete Good path without falling off.
Complete game killing only males.
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.
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.
Kill/incapacitate 235 terrorists.
Piss 100 gallons of urine.
Complete game using only melee.
Complete game using only the pistol.
Euthanise 30 elderly folks.
Kill 1000 unarmed bystanders.
Spend 900 seconds or more in catnip bullet time.
Respawn 20 times.