Below Zero lacks the charm and engagement of the original game on just about every level save one.

First, the map. The original's map was expansive and interesting. The one here feels kind of samey, being in some areas too mixed and without the same degree of layered exploration. In the original exploration felt very layered. Like every time you went deeper you were moving into a new world with a sense of fear and wonder which magnified as you found new strange locations such as the Lost River and below. Below Zero it lacks that. Instead they all just kind of merge together and the layout just comes off as bland. The closest they have is the surface exploration which, while not bad, is feels divorced from the core game play loop and is set up into this mess of canyons that just adds artificial challenge.

Second, the vehicle progression. In the original you work your way up from the Seamoth to the Cyclops. There was a sense of progression. In Below Zero you build the Sea Truck and just bolt new pods to the back and give it upgrade upon upgrade. And using the Cyclops vs. the Seamoth felt like a trade off in places. The cyclops was a mobile base, but it moved like a pregnant cow. The Seamoth was speedy and agile but weak and limited. You could bring both (at least until you got to the lava chamber) but that would mean leaving the Prawn behind. There were trade offs.

Third is the plot. In the original you were a simple survivor and the plot is discovered largely by vague hints and stumbling around blindly. You discovered it for yourself. It wasn't handed to you, you had to discover and explore and figure out what was going on for yourself. In Below Zero you immediately start with an annoying generic 'strong female protagonist' (not that anything is wrong with female protagonists, as long as being 'strong', 'female', and 'the protagonist' aren't the only memorable aspects of the character, like some soulless, self-propelled inclusivity checklist) who basically skydived naked onto an alien death world for 'reasons'. The plot is driven by an endless stream of poorly written exposition that manage to be memorable in only how annoyingly it can kill your immersion and coupled to 'helpful' way points that remove much of the impetus to explore.

One thing to note about the plot is that it was completely scrapped and rewritten halfway through development. It's one of the reasons the story comes off as so disjointed. The reason that everyone mysteriously vanished from the planet was because in the original plot the planet was abandoned after a meteor storm caused everyone to evac to an orbital station but Robin was left behind, but the station was severely damaged meaning that they couldn't go back down for her and it went from there. The current plot was shoe-horned into existing map assets, like a DLC of a DLC, and it shows. You can see this because the game has two stories that are not only completely disconnected, but one of them which was the reason you came there to begin with seems to drop off the map 30 minutes into the game and it's almost too easy to miss it due to the second feeding you a series of breadcrumbs that leads to the endgame.

In general, they missed the simple factor that made the first game great. It wasn't Ryley the Protagonist's story. It was my story. It was your story. It was the players story. The voiceless blank slate character was simply a vessel for the player's experience. Below Zero is Robin's story, not the players, and frankly, she really ain't that interesting.

Then you have the creature designs which compared to the original are largely uninspired, drawing far too much from earth lifeforms to the point they seem less like strange and exotic alien lifeforms from a distant planet and more just strange and exotic prehistoric earth creatures. For example, you have the alternative to the Reaper Leviathan, the Chelicerate. It doesn't feel like as alien, instead its just kind of a giant death shrimp. Then you have the penguins. I mean 'pengwings'. Which are penguins.

Even most insulting is the fact that they actually had plans to add some well designed creatures to the game but chose not to because they cut a biome and thought that people didn't need excess creatures. The Ice Dragon Leviathan (check the wiki) would have been infinitely more interesting than the mega-shrimp we got.

The only improvement over the original is base design, which is largely due to the addition of some additional rooms and decorative elements. A very welcome addition but it kind of falls flat when combined with the everything else.

In general, this is an all around inferior product that shouldn't be bought for full price. If you find it for half off, loved the original, and don't mind being lead around the nose by Lady Generica and her boring sidekick, go for it... but don't pay full price. It's not worth the money.

Update: The game being finished does nothing to change my opinion.

Note: Having thought about it, I'd almost like to say the theatrical trailer manages to be both a case of gross missadvertisement and the game they should have made. No bland voiced protagonist, just some poor sap trying to survive on a planet that seems hellbent to making them suffer. Wouldn't even have had to of replace the character model as I find absolutely nothing wrong with the idea of an everywoman protagonist...