This game is awesome but extremely poorly made. I know I am in a minority when I say I really enjoy playing through the campaigns of COD, but whoa, when multiple levels have MULTIPLE glitches where levels go on for infinity, key weapons don't appear in order to finish levels, companion characters just vanish!! I guess the more we move towards multiplayer the less we care about quality testing. Why develop a level properly when you can just say, "Let the players make the action happen." This is a Beta, not a fully tested and developed product. But if your core group is just 15 years olds who just like shooting each other then I guess that's what the audience demands.
To literally see tons of posts that say, "oh yeah, it's super glitchy just restart from the checkpoint and maybe it will work, other wise just redo the mission..." Lazy.