I bought the game the day it dropped on Steam into EA and tried it out for what they had to just get a taste of what to expect. I let it sit till it went gold just keeping up a little on the news so I wouldn't hit spoilers this time like the first game.
So I wasn't attached to the story they had (nor really knew anything of it) so I'm personally not bothered that it was changed, what you don't know don't hurt you type of thing.
That said:
I'm so annoyed. Subnuatica BZ ending is like one of those movies that just ends without telling you how it worked out. The voice actors just say basically it's "50/50 who knows". Went a total spoiler free route with that but I'm not happy with it.
First words out of my mouth I said out loud without thinking as credits started "That's it?".
There's other parts of the story that just make no sense. Like everyone leaving when it's clear things can be fixed and work could easily continue (heard by PDA) Alterra leave like there is deadly radiation or something. Nope a little rubble and gone. What?

Gameplay wise it was fun but less so than last game, wasn't as many "Oh ♥♥♥♥ this is where I die" moments.

The game felt, I wouldn't say rushed, but it wasn't done very well.
Last game to play the game well you had to build at a minimum the Seamoth and the Prawn Suit to complete the game. In BZ you honestly only need the Sea Truck with the depth mods. It was fun having to plan out what you wanted to do in the first game. Going all the way down to bottom? Ok need your Prawn suit. This one the Sea Truck is plenty.

At the start I had the same feeling of "danger" like the first one but as I kept playing I noticed things barely even tried to attack me and that's when the game started to become boring to me. I can count on one hand the times my Sea Truck was grabbed on one hand and the majority of them were at the "deepest" point of the game. I died a grand total of three times in the game. One because I didn't pause the game like I thought I did when I stepped away and the other two because I was curious how two of the leviathans killed you.

Now while this makes it out like the game is the worst thing I've ever played it isn't.
I did have quite a bit of fun playing it and loved the building side and deco you can do now. Even with the game being set in a really shallow part of a water world exploring was fun I did have those "Wow that's cool looking" moments.

I will "Recommend" the game but if Steam gave a star rating I'd give it a solid 3 out of 5 stars.