This article contains mild spoilers for Subnautica and Subnautica: Below Zero.
It doesn’t matter how open your open-world game is — sooner or later your players are going to try breaking out of their sandbox. So how do you handle it? In the case of Subnautica: Below Zero, Unknown Worlds has devised a way of penning the player in without making it seem like an insult, a slap in the face that you’ve dared to wonder what’s “out there.”
There are few things more immersion-damaging than seeing a warning message flash across the screen, followed by a near-instant game over. Some games do attempt to use geography to corral the player; Fallout: New Vegas, for example, has mountains that bar your progress. But there are still areas where, if you roam far enough, you slam into an invisible wall, as is often the case with similar titles.
I’m not advocating infinite, procedurally generated worlds; there’s enough busywork in open-world games as it is. What is infuriating, however, is when designers have a solution right in front of them and they overlook it. Take Mad Max, set in a post-apocalyptic landscape where water and gasoline are the two most precious commodities in the world. Run out of the latter and you’re walking. Run out of the former and you’re dead. So, when I drove off the map into the Big Empty, I knew it was a death sentence.
But I wanted to see how I could get into the wilderness. I’d drive as far as I could before stumbling out, walking as far as my feet could carry me. It was stupid, yes, but it promised to be entirely keeping with the barren hellworld of the Mad Max quadrilogy. What actually happened was that my health bar started ticking down the moment I left the boundary, as if Max were suffering some horrifying arterial gusher. Twenty seconds later, he was dead and I was yanked right out of the game.
The solution used in Subnautica: Below Zero, on the other hand, is nothing short of brilliant. There are no invisible walls, no mountain ranges, no screen-dominating message, nothing as immersion-shattering as that. No, Subnautica: Below Zero’s answer to players wandering out of bounds is beautifully simple: It’s fear.
As was the case in the original Subnautica, Below Zero’s lore explains why there’s an ecological dead zone around the map, why the ocean floor drops away into a massive abyss, deeper than anything you’ve explored before. Just sitting there in your Sea Truck, gazing down into the gloom, is enough to tie your stomach in knots.
But mustering up your courage, you proceed, onwards and downwards, as deep as your modular submarine will allow. Then you hear it, the sound of some titanic creature. God help you if you’ve read any Lovecraft recently. Your mind is racing, wondering what horror has you in its sights.
It should, by rights, be an anticlimax when the creature swims into view, making a beeline for your fragile vehicle. You’ve seen a smaller version of this beast before; normally, it’s not even the biggest Leviathan Below Zero has to terrorize you with. But surrounded by the blackness, unsure which way is up, it’s every single nightmare you’ve ever had.
Panic seizes you. Do you keep going? Maybe you consider abandoning your craft in the hope they’ll choose it over you. But then you think about the blackness, and you push onwards, afraid to turn around for fear of what you’ll see closing in on you, jaws big enough to bite your Sea Truck in two. You’re still shaking, praying you can outrun the beast snapping at your heels when the second Leviathan swims into view.
With the exception of Subnautica: Below Zero’s Creative mode, where you’ve willingly stepped away from the story, trying to leave the map always ends badly. But it’s the memory of that first encounter that should make you think twice about trying again. Logically, I know Unknown Worlds hasn’t crafted some hidden horror that will rise from the depths should I evade the beasts Below Zero calls “Void Chelicerates.” I’ve even looked on the Subnautica: Below Zero wiki, but when I think about that void, logic doesn’t matter.
It’s that terror that’s kept me within Subnautica: Below Zero’s boundaries. It lacks an automap so I don’t even have the comfort of knowing for certain I’m approaching the edge of the map. Every time I saw the floor dip away, I’d pause, wonder if I was approaching the edge of the abyss, mind flashing back to that first encounter — short of administering an electric shock through my joypad, there’s no more effective way of ensuring I don’t stray.
Granted, not all open-world games have the option of using fear to rein in their players. There’d be a few raised parental eyebrows if little Billy was playing Lego City Undercover when some towering, blocky abomination burst through the ground. But Subnautica: Below Zero’s approach is a stroke of evil genius. It’s a much-needed take on how to keep players within bounds without wrenching them back to reality and something I’d love to see other developers build upon. If I never see “LEAVING MISSION ZONE” again, it’ll be too soon.