Originally Posted by G3 Camo
I HAVE KINDA FIXED THE GLITCH!!! it worked for me and my friend. We finished playing in Co-op niether get an achievement we start over i was host. we play the first mission and he gets the achievement. i beat the game again with someone new in Co-op still no achievement for either of us. my friend makes a lobby co-op and we beat first scene of first mission i get the achievement.
thats what happen idk know if thats how it works but that happend for me
I didnt get the achievement first of all so i tried getting my friend to host the coop game and did act 1 scene 1 and i got the achievement so i can confirm that this works