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