Subnautica and Subnautica Below Zero are both games created by Unknown Worlds. In both, you find yourself on an ocean planet, trying to survive as you discover the mysteries in their depths. Although Below Zero is only in early access, there’s still enough of a plot to piece together a theme, many themes in fact. Some of these are in contrast with Subnautica’s, some of them compliment them.

Let's start by summarizing Subnautica. You crash land on an alien planet and fight to survive against all the creatures around you - that you barely understand - and the disease that you contracted upon landing. Not only do you have to find a way to escape, but you need to find a cure to do so. There are more broad themes of exploration, discovery, and learning about the unknown. Everything you knew about is gone, as seen through the life pods, abandoned PDAs, and countless reminders from your own PDA. The overarching theme is "Man vs. Nature" or alternatively, "Man vs. The unknown/What they don't understand". Knowledge is power, but now that they're in a place where they don't understand what else is with them, they don't have their power anymore. There's also the theme of "How far will you go to survive?" As you dive deeper into the depths, more and more crazy creatures reveal themselves to you.

And eventually, it's the Sea Emperor Leviathan that saves you and Alterra who gets you off the rock. The former gives you the cure to your disease, the latter gives you blueprints for an escape rocket. The Sea Emperor's story is done, dying by the time you leave the planet, but Alterra still has their presence. In game, Alterra is just a vague and looming presence, but they haven't done much, apart from saving you. But, the very end of the game [and those PDA files from the Aurora] might make you question otherwise.

Now, the Below Zero DLC. You - or Robin - have now been sent to this world so you can learn about it. What forces you under is a storm that destroys your research base. You listen to your sister, Sam, for instructions on what to do. Then, you found Al-An and accidentally downloaded them into your brain. Now you're suddenly forced to hide from the whole of Alterra, and your sister. Jefferys, who went missing at first, who you were also supposed to find, had some suspicious PDA entries, that Al-Al wiped for you before you sent it up. You begin to lie to Sam about what's going on, who is a person that, as pointed out in the beginning, you shared a womb with. And not only do you have to trust the alien in your brain, but there's also someone else on the planet, one that you have to work with. There's still the theme of discovery, but it's more hush hush, and goes alongside the theme of hiding and lying to save your face, along with the alien in your brain. And with that, there's also the theme of nothing looking as it seems. This is where the overarching theme becomes "Man vs. Man", "Man vs. What they thought they understood", and the most terrifying - if it becomes true - "Sibling vs. Sibling". Alterra is not your friend here, and we as the player are seeing their true colors. The massive corporation that they are is larger than we thought and more terrifying than what we could read in the base game. And with Robin trying to protect Al-An and Sam trying to protect her, it gets the theme of "How far are you willing to go to save someone else?". For Sam, it's a sister, for Robin, it's an alien. It might seem like different ideals, but I give you this.

Robin said for herself that finding an actual alien is the holy grail for Xenolinguists. She found one, and now there's a chance that they might be destroyed if they ever get into the hands of Alterra. As far as she knows, they're the only one left alive. As far as she knows, she's saving a species, something she feels inclined to do, as seen in the recovered family logs with the Auxwillian Toad Worm.

And who are our allies? Well, they're far and few between. We can hope that Sam will continue protecting us, even if it might forsake her ability to get promoted. There's Al-An, who's trying to get along with us in our head. And there's Marguerite, a Degasi survivor mentioned in the base game who somehow survived to get all the way down to the Arctic Zone. And as far as we know, without anyone else from the Degasi.

So, we have our contrast in what our main antagonistic force is and who we're relying on to help. But, you might say that both games have you fighting against the wild. And yeah, it does, but in Below Zero, that's not who you're fighting in the main plot. Subnautica's antagonist can be summed up to all that you don't understand. Below Zero's antagonist can be summed up to all that you thought you knew.

But, there are still similar themes to be seen in both. Knowledge is still a huge theme, levels of which also apply. Individuals over the masses also reign supreme. Corporate greed is also in there, more in the background in Subnautica, but full force in Below Zero. A sense of isolation, although more psychological in Below Zero than in the base game. Conservation is one seen through both. And one of peace instead of violence, as seen through Marguerite in both games.

Honestly, these two games are in balance with each other over the theme. And if there's one thing you can say about them, it's this.

They are different, but they go together.