Here is the full list of all 20 John The Zombie achievements.
Score 2000 points by causing chaos.
Score 1000 points by causing chaos.
Score 500 points by causing chaos.
Attack 5 cops.
Learn 10 skills.
No agressions for 10 minutes.
Catch one big fish.
Eat 10 cow's brains.
Score 50 points in basketball.
Eat 50 brains.
Kill 20 zombies with a car.
Eat 30 brains.
Learn 5 skills.
Eat 10 brains.
Win the first race.
Win the second race.
Win the third race.
Finish the campaign.
Win the first horse challenge.
Win the second horse challenge.