Not very interesting and hard to follow.
The campaign in this game is pretty short. You spend most of your time wandering around dark streets. There are a couple levels to brighten your day, but most of the time you'll feel like you're in a First Person version of Resident Evil (The old ones). In each short level, you may encounter a couple waves of enemies. They are pretty easy to eliminate and don't pose much of a challenge. I beat this game on Normal first, then again on Legendary. The difficulty didn't change drastically. In fact, it stayed about the same. So, if you beat this game on Normal, I recommend you try it on Legendary. Pressing on, I found this game to be interesting, but not a good kind of interesting. The story bounces around from character to character and if you're not paying attention closely, you will not understand what is going on. In this sense, it reminds me of a Call of Duty game. Definitely not a direction I want Bungie to move in.
Overall this game seems like a Demo/Beta. Bungie may have released this game for two reasons.
1: Obviously Money.
2: Too see our opinions, as fans of the series.
Well, my opinion is - Please don't go in this direction. I don't like how the story shifts from player to player. I want my over-shield back, and health regeneration. I don't like having to use Med-Packs. I don't like the lack of action. I wouldn't mind if there was more to the story, but walking around aimlessly is not my kind of fun. The VISR system is okay, I guess. We'll see how they work with it.
I'd just like to say in closing - My review is only based on the campaign; Nothing else. I didn't try Firefight Mode yet, and the Multiplayer PvP is Halo 3. Thanks for reading.