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