Here is the full list of all 50 South Park: The Stick of Truth achievements worth 1,000 gamerscore.
You defeated the Boss Hall Monitor while wearing freckles.
You shat your pants during a boss battle.
You've farted on animals 25 times.
You opened all of the garages in South Park.
You befriended both crab people and gnomes.
You've farted on people 100 times.
You defeated Princess Kenny and recovered the Stick of Truth.
You've farted on every buddy in the game.
You've spent $500.
You made friends with half of South Park.
You befriended your father.
You have collected half of the available costume sets.
You befriended the Goths, like everyone else playing this game.
You defeated the Grand Wizard Cartman in battle.
You farted on 10 enemies in the world that were knocked out.
Over the course of the game, you've scored 100 perfect attacks.
You collected 15 Chinpokomon.
You sold 300 junk items.
You've unlocked all of the upgrades for a New Kid ability.
You completed your first day in South Park.
You have joined the KKK.
Over the course of the game, you've blocked 100 attacks.
You found Jesus while playing as a Jew.
You successfully blocked every enemy attack in a single (non-tutorial) battle.
You collected 5 Chinpokomon.
You flung a turd of your own creation at an enemy.
Defeat Kyle in battle.
Let Gingers bite you 3 times without blocking.
Summon Mr. Slave while in Mr. Slave's colon.
Sell nothing the entire game.
Defeat Princess Kenny while looking like David Hasselhoff.
Fart on the Mayor, Father Maxi, Principal Vic, & Prime Minister.
Name yourself Douchebag.
Fart on a canine enemy while in Gnome form.
Hit 3 enemies with a single fart outside of combat.
Defeat Princess Kenny while in your Makeover disguise.
Interrupt 5 channel attacks with a fart.
Defeat the Meth Tweekers while wearing the Evil Cartman goatee and the bald cap.
Defeat Kenny while sick with Dire AIDS.
Watch your parents have sex for 60 seconds.
Defeat at least 3 enemies in one battle while your buddy is unconscious.
Complete the game without ever ending a combat with a buddy knocked out.
Collect all the Chinpokomon.
Befriend all of South Park.
Kill 20 enemies with Cartman's ass.
Shit Your Pants in battle three times.
Complete all available Costume Sets.
Fart on the corpse of an aborted Nazi Zombie fetus.
Have Kenny Die 10 times in battle over the course of the game.
Collect all the weapons and costumes available in the game.