I grew up playing the Halo games and fell in love with the characters and the amazing story it held, so it is safe to say that I am nothing but EMBARRASSED when it comes to this show. I do not understand why they cannot follow even the most basic setups the Halo story has, like the fact that ALL humans can activate forerunner artifacts, not just "The chosen ones", all for a quick cash grab.
Pros:
They did a good job with the design of most things like the UNSC vehicles and the armor itself looks well-made.
There are some good action scenes (especially Chief hijacking that banshee which reminded me of the good old days when hijacking your friends/family was the best feeling ever)
Dr. Halseys acting is quite good and it feels like she's actually trying lol
Cons:
Where do I begin, well one of the most annoying things about this show is that the chief takes off his helmet every chance he gets. I get it, the actor clearly wants everyone to see his face but who in their right mind would take their helmet off in the middle of a bloody warzone. The idea with Chief is that we can understand the emotions he is conveying without seeing his face, that's how well he's written in the games but the show writers just cannot comprehend that.
There is some questionable CGI like in the first episode with the assault rifle, it was an unnecessary scene that could have easily been deleted.
The elites look odd, they look like slugs. If those elites seen in the first episode were some low-ranking elites then that would have been fine but they all look like that.
Cortana looks very strange
Why can a human control the worms (Hunters), why is this possible
Why can Chief just be turned off by Cortana (when he did that goofy ahh jump at Halsey)
Why can only select humans to access forerunner artifacts, the whole point is that the precursors gave humans the ability to do this yet now they limit it to 2 people
The guns that the rebels are guns that we use now.... even though its set 500 years into the future
Kwan is just completely useless and I skip forward every time I see her
These are just some of the issues the show has, there could be more but I stopped watching the show after seeing Chief and Makee together
To summarise, paramount had the opportunity to make millions from a show that they didn't really need to write a story for and yet still managed to fail. The games and books already exist, they know what the people want such as the flood, the arbiter, Sergeant Johnson, and Noble team. Imagine the hype if Chief goes rogue and you hear that a highly skilled assassin called Noble 6 has gone to track him down! Or when Chief and some marines meet the flood for the first time and it becomes like a horror movie, conveying the true terror of the flood infestation! The potential is there yet paramount act blindly for some quick money
TL.DR: Paramount took a great story with great characters and massive amounts of potential and threw it down the drain with terrible writing for a quick cash grab.