Okay, this thread is really big (3 pages long with my 50 posts per page setting), and using the search is not helping me. So if the question is a repeat, I apologize sincerely.
Is there any achievement at all in this game that you cannot get in co-op? Like are you forced to play in solo for any achievement at all?
I am not being lazy in asking this. Halo: Reach had a solo campaign achievement, for legendary, and I got it in the first 10 - 20 hours of the game officially releasing (you can check on my Xbox Live page). I am not lazy, I just do not buy games and pay for Xbox Live to do things solo.
Everything is Permitted, and Nothing is True.
I am negative infinity. I am the manifestation of nothingness. My power is the lack of existence. The lack of existence can pull all things that exist to fill the void. Thus, my power is everything, and yet nothing. And even still, it is not a contradiction. I am negative infinity.