I've had 2 different issues with Halo 4, was wondering if anyone else had run into these:

First, I've been playing the campaign co-op, and it seems like if we stop mid mission for any reason, then come back and finish it we aren't getting credit for the mission when we finish it. For instance, we've completed through Reclaimer (mission 5), and can select all the missions up to that point, but it does not show Forerunner or Infinity (3 and 4) as completed for either of us. We stopped at checkpoints during the missions and restarted at the right rally point when we came back, but it just didn't count it. Didn't get the achievements either. Curious if this is just how it works in all cases, or something glitchy? Some of these missions are pretty long to require you to do it in one sitting.

Also, my game ran perfectly fine the first day playing it, and my brother's seems to run fine too, but yesterday I had constant stuttering (I guess that's what you'd call it?). Basically every 10-20 seconds the screen would lock up (as in, 0 frames/sec) for about 2-3 seconds. Kind of annoying, and I'm not sure if my old xbox is dying or if this is a common issue?

Any other GB dudes experiencing these, or have any suggestions about my stuttering issues?

I have not been playing it coop, but I've experienced neither issue you've mentioned. Always remembered my progress and the whole experience was butter-smooth for me.

I played the first couple missions co op and I have experienced the same thing. Like it either locks up for a second or the controls just don't respond. I'm going to blame it on connection though unless I hear more people experiencing the same thing. In multiplayer quite often I start matches not being able to sprint until I die once.

My friend and I went through the campaign on heroic. When we finished we noticed it didn't count us as completing the last chapter and chapter 7. Lots of weird online issues as well.

I can confirm that some chapters don't show up in the achievement list as completed. I didn't get the cheevo for the ending.

@Wess: I played on-the-couch co-op with my brother, but I jumped in midway through the first level. Neither of us got the achievement for finishing the first level, so it seems that resuming at a checkpoint does rob you of credit. I haven't experienced any stuttering, though.

Well it seems like the progress issue is fairly common. Interesting that it seems to be showing up mostly in co-op, does anyone know if this is an issue when playing solo? Might be some issue with co-op players being slightly out of sync somehow, even if you were playing together the whole time? Regardless, if you care about the achievements, seems like its best to play levels through entirely without leaving the game.

I'll see if I still get stuttering when I play next. Hopefully not.