Here is the full list of all 13 Organ Trail Complete Edition trophies - there are 9 bronze, 3 silver and 1 gold.
Beat the game five times.
Find your own grave.
Become a zombie.
Someone died of dysentery.
Have $1000 on you.
Put down an infected party member who has passed out.
Make it to Safe Haven with someone named Romero in your party.
Beat the game on Difficult
Fully upgrade your station wagon.
Kill 500 zombies.
Successfully forde a horde of zombies 3 times.
Kill 25 zombies without missing a shot.
Don't pull the trigger.