Halo 3 question please answer?

[( - _ - )]

if i do co-op play with someone on a mission will i get the achievement for completing the mission anyway
add me MaTtkirby007

 

[yo yo]

yes
bungie made no benefit for loners playing the campaign
the only hard thing is getting the points on the meta campaign to fulfill the needs of the achievements in coop, u have to share kills with a partner