Upon replaying the campaign missions for metagame highscores, it struck me again how incredible they are. I don't understand why people complained about the campaign, for me it's easily the best of the three games. It perfects the formula and the 'samey' level design people complained about is practically gone. The structures in The Ark were very similar to eachother and Crow's Nest wasn't such a great location, but apart from that... very diverse and so fun to play. It was also for the first time that I actually observed the Brute team mechanic and smirked when I heard a Chieftain say something along the lines of 'you flush him out, pack brother' and watched the hierarchy in the Brute lineage in action. The Brute pack in Crow's Nest is one of my favorites. When you stay behind the perfect metal shelter for too long, some Brutes will eventually come and get you and even destroy the cover.
I'd go so far as to say that missions like The Storm, Ark and Covenant are the very peak of the series. Whoever designed the structure and variation for The Covenant deserves a feather on his hat. Also, Sierra 117? Best first mission in a shooter I've played. I keep coming back to it. I will say though that like many, I'm not a fan of the Cortana level. I'm postponing my playthrough of that and I did the same on my heroic run. It's a shame because they balanced the appearance of the Flood so well in the game, until you once again had your fill of them in that mission.
It's the third time I'm playing through these missions and even after completing the metagames I can't wait to play this game in co-op on legendary (I haven't even played the game on co-op thus far - gasp)