This is a sad review for me to give, as I had high hopes for this one. I guess I should've known better, since 343 doesn't have a great track record, but I gave them the benefit of the doubt. Well, I'll keep this short and bitter-sweet: the gameplay is excellent, really feels like a proper evolution of the Halo style; the campaign is okay, but nothing that wows me as an old Halo fan. The multiplayer... that's where the curse has fallen upon this game. The multiplayer has a tiny selection of modes, a smaller selection of maps, and a progression system dreamed up by Satan himself. You need to complete challenges to get any xp, and these challenges are as random as they are arbitrary. Yes, you can gain a small amount of xp from a challenge that says "play a game of PvP," but that has diminishing returns. No longer does your performance or medals affect how much xp you get. Now, it's up to Microsoft RNG to get challenges that are actually fun--that don't force you to work against your own team mates. Or... if you got a credit card, just buy stuff! You know, like a proper free-to-play game.

TL;DR: Multiplayer is fun, but it's hampered by terrible levelling, a lack of content, and greed. As a Halo fan, I'm sad to say that this game is not worth your time. Go pick up Halo MCC instead.