Here is the full list of all 35 Postal III achievements.
Kill 1000 unarmed bystanders.
Spend 900 seconds or more in catnip bullet time.
50 kills using cat.
Return Thegways to the owner
150 kills using fire.
50 kills using bees.
Kill/incapacitate 235 terrorists.
100 kills using machete in melee.
Euthanise 30 elderly folks.
300 headshot/decap kills.
Smash 50 windows.
200 kills using M-60.
Piss 100 gallons of urine.
Destroy 50 cars.
50 badgersaw kills.
50 kills using boomerang machete.
Suck up 500 items with the shop vac.
Escape from prison.
Complete game using only the pistol.
Complete game using only melee.
Finish your business with Krotchy.
Choose path for the first time.
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.
Injure yourself.
Respawn 20 times.
Take out all the criminal scum infesting Catharsis!
Arrest eco zealots leader.
Arrest 200 perps.
Taze 200 victims.
Disobey orders, given to you, and see what happens.