Excellent sequel to Subnautica.
There's a superb story and great graphics.
The new biomes and animals are also very cool and it's a whole new experience!
Definitely recommended!

Visually, it's a bit nicer!

Now for the cons:

How do you even write a story where I find myself mocking the protagonist and her dead sister, while agreeing with the "big bad corporation" antagonist? And not because I'm an ♥♥♥♥♥♥♥, but because Alterra’s official report says it was a workplace accident caused by Sam’s recklessness.. and that's exactly what we later confirm in the story.. Alterra's report is 100% correct and no foul play is ever exposed. She was careless and got herself and a colleague killed.

The explorable map is smaller and somehow feels less deep and rich than the original.

Leviathans are smaller and feel less intimidating.. and there's only 6! Literally less variety than the original's 8 (not including the dead one).

And the vehicles... oh the vehicles..
No Seamoth.. no Cyclops.. just a wet delivery van..
It's slow, ugly.. and if you actually want to use it to.. idk, explore the map? Forget about having carriages! It only gets slower and harder to maneuver or fit in caves.. the compromise feels like it started before you even add a carriage.

The saying goes "If you can't make it perfect, make it adjustable.", not "Make it ♥♥♥♥, and then make it ♥♥♥♥♥♥♥ when you adjust it."
This thing wouldn't even make a good train, at least trains TURN with the tracks, this thing is a rigid log, something you might slap together in TerraTech.

That bait-and-switch at the start wasn't just for the funny- I genuinely can't think of any other aspect where this game shines.. it is a step down in every direction. By itself, it's a fine game, and had it been released first, it would have been a very good game. The order of release would be very confusing to someone who played them both without any chronological context..

Below Zero is the weaker game by all accounts, "Subnautica" feels like it should have been released second as it feels like a step up from every aspect of Below Zero..
Subnautica is the sort of game you can expect to see after the devs learned from the criticism that came from Below Zero.. how this is the other way around baffles me.

Don't play this game expecting: "Subnautica, but more refined and with snow!"
In fact, you'll likely experience the least disappointment if you play this one first, then Subnautica; end on a high.

The game itself is okay and the graphics are great compared to the original Subnautica in my opinion. The problems I personally think make the game iffy is the balancing of minerals especially in deeper caves, it is way too easy to find rarer minerals, another issue is that a portion of things you make are just nearly useless, for example, the headlight sucks because you could always just use the seaglide light and you always have to replace it with your rebreather making it so annoying to use, this goes for some other items in the game but I don't wanna ramble too much about them. The story of you the main character and you finding what happened to your sister just sucks and is more focused of the other storyline which I will not say for non-spoiler purposes. In general this game is 6/10.