I've completed the whole game except for some chests a few propaganda posters, and a couple letters. All missions are complete including the Hurk's Redemption missions. I saw the cutscene with Hurk showing off the Impaler but I never got it to use myself. How did I miss it? Was I supposed to pick it up from somewhere or something?
I have the same thing, I believe this weapon is supposed to unlock after completing the last HURK Mission.
I just did that one which is the third, the one where you have to do a vehicle takedown from the buzzer (copter)
Unfortunately the Impaler does not show for me under signature weapons, shame as I was looking forward to using it.
List of weapons here.
http://www.primagames.com/games/far-...methrower-m-79