Here is the full list of all 27 Orc Slayer trophies - there are 10 bronze, 9 silver, 7 gold and 1 platinum.
Completed Level 2.
Completed Level 1
Slay 100 Orcs In One Level.
Slay 50 Orcs In One Level.
Slay an Orc with a shot to the Crotch.
Slay an Orc With a shot to the Head.
Find the hidden area within the woods.
If you were an Orc, you'd be dead.
Slay 200 Orcs In One Level.
Slay a Tank.
Slay 3 or more Orcs with a pigboom.
Slay the general.
Slay the Necromancer.
Completed Level 3.
Completed Level 4.
Completed Level 5.
Completed Level 6 .
Completed Level 7.
Completed Level Bacon.
Completed Level 9.
Completed Level 10.
Completed Level 11.
Completed Level 12.
Completed Level 13.
Slay 30 Orc Skeletons.
Find the hidden area.
Slay Big Bertha, the colossal hen.