Given this comment thread started with someone who hasn't played the first game, I'm just going to say THIS POST CONTAINS SPOILERS

Of the many things Below Zero does worse than the original, the overland sections are up there. The entire game is full of a lot of twisty turny self-similar maze-like environments, including the snow caves area. It doesn't help that you can't get a good look around because of all the weather effects. The way you get UP TO where you're supposed to go isn't easy to find. The large open area with the giant worm creature is, as you say, huge, devoid of anything interesting, and it's full of that worm, which had better be unfinished. If that is what they meant to build...I don't think I'm going to make any more purchases from this company. Same with the Snow Fox, which is the worst video game vehicle I'm aware of. Instead of a fast paced chase sequence where you look back over your shoulder at breakneck pace to dodge a giant monster chasing after you, instead you awkwardly bumble around an environment in a vehicle that feels broken and malfunctioning, unable to look around while moving or turning while stopped, and occasionally you find yourself standing next to your slightly damaged bike. It is. Utter. Assgarbage.

I also have some fairly unkind things to say about the overall story (which, they had a different story, they threw it out for a stupid reason and then janked out the retail story to fit the set pieces they had already built into the game), the monsters aren't as imaginative and more annoying than scary, and there are some inexcusable guide dang it moments, like how are you supposed to know where to get the superultramega computer dingus components from the wrecked ship?

though again, I think if I were to choose 10 screenshots to hang in an art gallery from the Subnautica franchise, almost all of them would come from Below Zero. The original game looked very good, but suffers from pretty bad pop-in in the distance, which BZ mitigated by shortening the draw distance. I like both soundtracks for different reasons; Subnautica's soundtrack is a series of cool songs, Below Zero's soundtrack is much more atmospheric; I almost don't process it as a series of songs, just how places in Sector Zero "feel." It's very well done.