Alright, so I've played a decent amount of MP and completed the campaign twice, once on Legendary solo, then afterward with a friend. If I had to grade it, I'd break it down like this:
Gameplay:
Gameplay is smooth and solid, and MP is better than ever. There are plenty of game modes, custimization options, and unlocks to keep you coming back for more. Gameplay is smooth and pretty balanced for the most part. If you are a fan of Halo style MP, you'll love this.
Graphics (CGI Scenes):
Wow...just wow. Possibly the most realistic looking graphics outside of actual live actors. I've never seen anything like this on a console, it's incredible.
SP Story:
The blemish on an otherwise perfect game. It's not bad, it's just meh. If I had to give it a grade, I would say incomplete, because Halo 4, 5, 6 were set to be a new trilogy from the start. Seeing how the Chief has been on hiatus for several years, it's tough to pull magic out of you know where and create something mind blowing; the story so far shows that. Again, it's not bad, but it's nothing spectacular.
Buuuuut....with that being said, I think it might be time for....
A NEW RAGE COMIC STYLE GAME/STORY REVIEW!!!! HALO 4 COMING SOON!!!!