I really enjoyed the first five-ten hours but was pretty disappointed after that. Once you've screwed around in the open world for a few hours, the game really doesn't throw many new ideas at you. The last like 5 missions that are all linear were really boring and too many of the boss fights were bullet sponges.
It felt like if they came up with one or two more grapple-hook level tools, then polished a few more things, didn't repeat the same three environments the whole game, it would have been something really special. As it stands, it really falls short of what I thought it was trying to be. It's hard to finish the game and not feel like they were just trying to reach a minimal viable product.
Story was whatever, the open world is cool and works with Halo better than I thought it would but there's not a lot to do after a while. Not as good as the older games, but the gameplay improvements like climbing ledges is so stuck in my brain I kept trying to do it when I went back to play Reach. I will say I hate quirky MCU-humor wacky-zany style characters and Weapon crossed that line a couple times for me.