Get's rid of almost everything that made the first game amazing for no good reason.
Dungeons being the main focus of the game was a massive mistake. They are boring, samey and way too long. The game is fun enough up until the fake ending, but DO NOT go for the true ending.

Breath of the Wild and its consequences have been a disaster for video games

Where did all these bee's come from, Back to the Future Part 0: Marty versus the Bee's? I don't think so.

I can honestly say that for the first five minutes I was playing this game I was mildly entertained!

What a bunch of assburgers, with a side of fries!

Yo Noid... Yo Noid? I guess just calling it The Noid didn't have enough pizzazz to it.

343 does it again. This game is simply unfinished. Now this is their best effort so far, but that isn't saying much.
This game has launched with the fewest maps and gametypes out of any Halo game to date.
The maps we have gotten are painfully dull. They are very strict arenas built for ranked play with little to none dynamic elements like man-canons, teleporters etc.
The gametypes included at launch are less then the bare minimum, there is no King of the Hill, no Assault, no VIP. The list goes on and on.
The matchmaking playlists is also a huge issue.
The game has only 2 playlists.
Quick play
Big Team Battle
(bot bootcamp and ranked arena is identically to Quick Play except for bot opponents or BR starts)
Mixing Slayer gametypes with Objective gametypes in the manner they have done in both playlists here is a terrible idea which encourage leaving games to play the gametypes you want.
Sprint, slide, clamber and ADS does not belong in Halo
343's equipment is better than Reach and 4's armor abilities but they work more than abilities rather than dynamic parts of the sandbox like the equipment in Halo 3.
The weapon balancing isn't the worst thing ever but some weapons like the Plasma Pistol and Ravanger are completely useless and the Assault Rifle is way too strong.
Vehicles are completely useless when they have now quadrupled down on Reaches health based system instead of CE/2/3's vehicle system. They do little damage and can't take much damage before exploding. The addition of electric weapons and the grapplehook makes setting foot in a vehicle more of a death wish than ever before.
Multiplayer progression is actually the worst thing ever and that's by design. By making any form of progress tied to completing challenges and not your performance in-game is only done to sell you microtransactions to get easier challenges. These challenges are usually extremely niche or absurd as well, also encouraging not playing the objective in matches.
Launching a Halo game without Forge now twice in a row is a deathblow to the potential this game ever had.
There is loads more the game also SHOULD have considering previous titles in the series, but not having Forge guarantees this games swift death.
The story painfully dull. Master Chief acts nothing likes himself, he gets pushed around like a wuss by the new AI and this random no-name pilot. He also never shuts the fuck up. The writing team has attempted to insert MCU humour into the game which falls flat on it's face every time. Not only is the dialog cringe but it's also padded to high heaven. There are so many words used and so little information actually being uttered. The main Brute that (I have already have forgotten the name of) Talks for waaay too long with out saying anything at all really.
This game is a Farcry game in Spartan armor. This Ubisoft formula is so tired and brain dead. This mapmarker hunting and outpost clearing is NOTHING like Halo CE's open maps like "Halo" and "The Silent Cartographer" which this campaign is supposedly inspired by.
Now most of the open world is kinda sorta optional, even without the Farcry game stuffed in the middle of this campaign you are stuck with a duller campaign than Halo 5. You go trough either read buildings or blue forerunner interiors. The layouts are copy pasted over and over again, is this some backwards way to make a homage to Halo CE?
The AI in this game is thankfully better than they were in 4 and 5, even better than Reach in some aspects. BUT they are better in the way they are not annoying like the previously mentioned titles. They are easily the dumbest and weakest AI in the series. I played this game blindly on Legendary without breaking a sweat. It's such a shame that King of AI in the series is still CE.
I could go on and on and on about Major and minor issues in this game. These are the biggest standouts to me as of this moment. I hate 343 for what they have done to Halo.