Here is the full list of all 29 Primal Fears achievements.
Bonus multiplier reached 50
Bonus multiplier reached 10
Find one newspaper
Kill 10 creatures
Kill 100 creatures
Kill 1000 creatures
Kill 5000 creatures
Kill 10000 creatures
Kill 15000 creatures
Finish the map Hospital
Finish the map Suburb
Finish the map Police Station
Finish the map Sewer
Finish the map Mall
Finish the map Laboratory - Secret Entrance
Finish the map Laboratory
Finish all missions in easy
Finish all missions in normal
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
Purchase all weapons in the campaign
Pickup 100 moneypacks
Finish a mission within time limit
Find five different newspapers
Find 12 different newspapers
Find all newspapers