I am stuck on legs shots as well. Loaded it and got headshots and torso. So I went and beat the game and didnt get it to count a single one of my tons of legshots.
Theres a glitch when I fought the second boss. He killed me and when I was coming back to life he died and it didnt count as a kill for me. Otherwise I would have had all 170.
 "The Last Stand 2"){kind=icon}
 "Achilles"){kind=icon}