Missing a lot of the first one's charm.

Whereas the original story was simple (you're the only one left standing - or swimming - after a spaceship crash; now survive), this one tries too hard to spread itself out in many different directions, most of which fail.
I usually would not spoil a game's story, were it not such a complete mess. Spoilers ahead for the game's whole "story".

There are three main threads that the game explores:
- Sam, the MC's idiot sister who killed herself on accident.
- Marguerite, a survivor from a spaceship crash a decade before the Aurora from Subnautica 1
- Alan, your alien buddy.

I call Sam an idiot because this is her plan:
The corporation she worked for has discovered an ancient virus, preserved in a frozen leviathan. They want to exploit this, by making medicine or possible bioweapons, etc. The usual big bad organization stuff. Sam wishes to put a stop to this.
She does this by synthesizing a cure for the virus. Great! Now she'll just administer it, and the whole plan is ruined! Nope. She hides the cure in a secret cave, then goes over to the frozen leviathan, plants explosives on it and detonates them... while she's still in the cave with it. So now she's dead. Darwinism, or something.

I will spend as much time on Marguerite as the game does, so this is where I have to stop. There's literally two missions involving her, both of which can be completed in a combined 15 minutes. Then you never see her again.

Alan is supposed to be the main driving factor of the plot. He's weak, and needs you to build him a new body so he can go home. Apparently, he also falls in love with you or something. Which is very odd, considering the only interaction you have with him are 2-3 minute phone calls whenever you've done something story-relevant. That's the issue; especially in an open-world survival game, the time between story-relevant activities can be really long. I took an hour or two out to go grind some materials, and then Alan and the MC continue their conversation right after as if I'd been speedrunning the game.


However, the story certainly isn't the only weak part of the game. Anything above water, in the freezing temperatures of the arctic, feels... rushed. It's empty. There's no resources to collect, maybe two different types of plant, one of which you can eat, and an enemy that you just need to avoid. I don't think the game planned for me to jet my PRAWN suit out of the water, since it completely negates cold temperatures and thus bypasses the entire cold suit/body heat requirement.

Underneath the water's surface, things aren't that much more impressive. There's, if I counted correctly, five different biomes. One of which is almost entirely useless: a crystal cavern in which only one new resource spawns. The other biomes are equally lackluster. The starting biome is probably the most beautiful, well-populated with different species and plentiful with resources. Going further out, you've got empty stretch of ocean with squids #45, and maybe if you're lucky a whale or two.
As for exploration, where the original Subnautica had submerged parts of the Aurora, crashed lifepods and old, abandoned bases to explore, S:BZ has exactly one submerged base, and one crashed ship. And the ship is entirely empty, aside from a nuclear reactor blueprint. Nothing like the giant expanse of the Aurora to explore in the first game. Kind of like they felt they had to put one in because they had them in the original, but didn't care for much more than that.

It's not a bad game, but it's not good either. Nowhere near the sense of exploration you'd encounter in the original Subnautica, nor does it have the sense of wonder. Having a living Architect, a species which is supposedly extinct, living in your head sounds like a really cool premise, but not when all he does is whine about how much he misses his people.

All in all, if you really liked the original, you'll get some enjoyment out of this one. Basebuilding is back, but with more added to it, etc. But don't go in with the expectations of a proper sequel, it feels more like a poorly made fangame.