You know I am surprised that this game has been so highly rated so far. For me it just falls flat. Don't get me wrong Infinite has some great ideas such as the boss fights and the open world, but the game as a whole does not stand up to the past games. Let me explain. And yes there might be mild spoilers, but I will try to keep them to a minimum.
First off the open world is very repetitive. I'm not talking about the environment or the graphics, but the missions you can complete in the open world. First of there are 3 basic missions you can do: saving squads, Boss battles, and capturing FOBs. There are about 47 of these missions give or take. I might have missed a few, but the thing is at the end of the day all these missions are the same. Kill all the enemies in the area. Well that's ok and its fun to wipe out enemies. There are a few variations in the boss battles and some have different kinds of enemies, but they really are just the same. Doing the missions over, and over, and over, and over, and over again gets boring and a little grindy. Some games try to over come the grindiness by making the boss battles harder. Which although it might be the same mission you still get satisfaction, because at least it was hard. Well in this game these missions get easier. The primary reason for this is because as you progress these side missions you get different vehicles and weapons. So you get to a point were you can spawn a tank, wasp, sniper rifle, or a rocket launcher whenever you want. As you can imagine this makes the game pretty easy.
Secondly there are about 7-8 what I would call mid tier missions. These are missions where instead of clearing out a whole base of enemies you destroy fuel silos or ammo machines. However these too are also fairly similar to each other and none are particularly difficult, and again get easier because of the whole weapons and vehicle aspect.
Lastly, I believe there are about 13 Main Missions. These are by far the best part of the game, or at least they are what I enjoyed the most. However, they took me the least amount of time to finish. I completed the entire game in about 24hrs of casual game play. This is for all the missions not just the main mission. I was not trying to go anywhere fast, and most of my time was spent completing all the side missions. I was kinda surprised that the game was fished so quickly, and in the end I was left wanting more, because I felt like the story was not even that developed yet. Also, without giving too much away they really rely on emotions of players who have played halo in the past. What I mean is I believe the campaign will be much less enjoyable for people who have never played Halo as they will not be as emotionally invested. I definitely expected more from the campaign of this game.
In the end I personally believe that this is the worst Halo game of all time. The open world is nice and graphics are good, but the missions are repetitive. The whole game takes about 24hrs to complete everything if you are taking your time and enjoying the sights. For an open world Halo game it defiantly falls flat. There are many other mission possibilities, but they chose to be lazy. I hope that this is not the trend for Halo. Although I know this will fall on deaf ears, and I hope you will disagree because then at least you had fun right?