Here is the full list of all 12 Choplifter HD trophies - there are 7 bronze, 4 silver and 1 gold.
Kill 100 goats
Kill 1000 chickens
Find all the secrets
Save Scoop on every level he is present
Get 5 stars on all the levels
Complete the game on NORMAL
Complete all "Escape" missions without killing anyone
Complete Desert Rescue without letting any rescuees die
Kill 10,000 enemies across all the levels
Kill 100 enemy soldiers on one level, without restarting the level
Complete a level by killing all the rescuees
Kill 1000 zombies