Here is the full list of all 57 Bunch of Heroes achievements.
Eliminate 723 zombie chickens, 821 basic zombies and 394 zombie astronauts
Complete all Mars missions
Complete all missions
Kill the Martian King
Eliminate 500 zombie astronauts
Defeat Fatzi
Complete all cemetery missions
Protect 50 cheerleaders
Complete a mission with full health
Defeat Fred
Complete all farm missions
Pickup every weapon in the game
Get to survival's wave 5 in less than 3 minutes
Eliminate 1,000 Basic Zombies
Defeat Jazzy
Defeat Pumpking
While in survival mode and playing alone: get to wave 3 in less than 5 minutes
Complete a mission without dying
Reach a combo of 40
Reach a combo of 60
Reach a combo of 20
Kill 200 Strong Martian
Complete 1 mission without picking up any Ultra Charges
Reload your extra weapon 1,000 times
Complete a multiplayer mission without damaging any allies
Eliminate 200 zombies with melee attacks
Eliminate 1,000 Zombie Evaders
Eliminate 100 Martian Teleporters
Eliminate 1,000 Radioactive Zombies
Eliminate 100 Flying-Saucers
Eliminate 200 Martians with melee attacks
Eliminate 1,000 Walking Coffins
Eliminate 1,000 Generals
Eliminate 1,000 Zombie Chickens
Burn 1,000 Zombie Chickens
Place 100 turrets
Kill 5.000 Martians
Complete a mission without picking up any weapons
Check out the Credits
Complete a mission with each of the characters
Eliminate 1,000 Zombies with bayonets
Eliminate 200 Martian with shields
Roll 20 times while on fire
Eliminate 200 Zombies with market cars
Complete 10 4-player missions
Perform 100 Ultra Attacks
Pickup 1,000 weapons
Eliminate 35.000 zombies
While in survival mode and playing alone: get to wave 3 without having been damaged
While in survival mode get to wave 12 playing alone
Perform a 80 kill combo while in survival mode
Kill a Martian Teleporter in survival mode
Get over a 1.000.000 points in survival
While playing with 1 ally get to survival's wave 6 without anyone dying
While playing with 2 allies get to survival's wave 9 without anyone dying
While playing with 3 allies get to survival's wave 9 without anyone dying
Survive up to the 20th wave in Santa's map in any difficulty