Here is the full list of all 29 Primal Fears achievements.
Finish all missions in easy
Finish all missions in normal
Finish the map Laboratory
Finish the map Laboratory - Secret Entrance
Bonus multiplier reached 50
Purchase all weapons in the campaign
Finish the map Mall
Kill 1000 creatures
Finish the map Sewer
Finish the map Police Station
Find five different newspapers
Finish the map Suburb
Kill 10 creatures
Kill 100 creatures
Finish the map Hospital
Finish a mission within time limit
Find one newspaper
Bonus multiplier reached 10
Kill 5000 creatures
Kill 10000 creatures
Kill 15000 creatures
Finish all missions in hard
Finish all missions in insane
Bonus multiplier reached 100
Bonus multiplier reached 200
Finish a mission in difficulty hard without being killed
Pickup 100 moneypacks
Find 12 different newspapers
Find all newspapers