Survivors!
As promised, we are back for Part 2 😎
Today, we are diving deeper into the technical and visual challenges behind the game’s expedition system.
Let's jump straight into it!
Underground Expeditions: Welcome to the Endzone!
One of the most ambitious changes? The new underground expeditions, including the Endzone bunker system, a name-giving location in the world’s lore.
These levels posed unique technical challenges.
“The systems are optimized for the above-ground world. Underground, we had to create an illusion, and spawn another world and hide it from view,” one developer explained.
It would definitely break the immersion if as a player, you noticed you were actually floating 1,000 meters up in the air, above the map..!
Lighting and textures
The illusion of being underground relied heavily on visual trickery and precise technical work.
Lighting, for example, had to be reworked entirely to fit these new locations.
When designing those expeditions, one unexpected challenge popped up: the sun.
You’d think in a bunker 1,000 meters below the surface, the sun wouldn’t be much of a problem… but as you now know, the bunker isn’t actually below the ground, and the sun is deeply baked into Endzone 2’s rendering system.
So, since removing it wasn’t exactly the best option, the devs decided instead to freeze it at a certain position and tint it a cold, unnatural gray-purple, and put it 90 degrees on top at its perfect zenith to avoid any shadows that would look weird underground!
But then, what happens to areas the player can’t reach or see? What should the walls of the world and the areas around the underground buildings themselves look like?
Well, you guessed it, here again the team had to experiment with textures, starting with inspiration from Fallout 2: raw earth textures that worked well for low-res pixel art.
But in Endzone 2, they didn’t hold up. Eventually, the devs landed on a solution: perfectly black textures extracted from the very few perfectly black pixels available, and enhanced with carefully placed lighting. The goal? Darkness that felt real, not shiny, flat, or fake.
Pathfinding
But visuals weren’t the only challenge.
The pathfinding system wasn’t exactly *thrilled* about verticality. The higher you went in the scene — and remember, these underground expeditions are technically floating far above the normal world — the more unstable and slow pathfinding became.
It added heavy strain on performance, especially compared to rendering, which handled the complex environments surprisingly well.
Modular design for a seamless flow!
These underground zones also rely on a layered level-loading system.
When you change levels in an underground building for example, the game unloads all other layers and then adds back the relevant ones based on your tracked position, starting from the bottom, and stopping at the level where you, as a player, are at this point in time.
This means the game is constantly checking where you are and only loading what’s relevant, which keeps performance smooth; even in a multi-level underground facility.
Another good example of the challenges verticality brought is the elevator shaft. It is very deep and not easy to navigate.
To improve the experience, the team tied the camera to the explorer on the vertical axis to have a smooth transition while going up and down, and worked hard to bring an immersive experience and manage light sources so they wouldn’t float or behave unnaturally when those walls disappear from view.
Lighting, here again, was a tricky one. Since the game engine automatically hides the back sides of walls, any light that was placed on them would just… hover in mid-air. So instead, the team had to anchor lights to structural elements like pillars, to keep everything grounded.
Wanna see a teleportation trick?
One of the coolest technical tricks? You can walk in and out of the underground bunker with no loading screen, no button press — nothing.
How, you might ask?
Well, there’s a teleportation trigger placed at just the right spot at the elevator’s entrance/exit. The moment you walk into it, the game teleports you from the floating expedition level back to the surface base, and vice versa, all without breaking immersion.
This is the only place in the game where the player is teleported without any direct interaction.
“We had to be extra careful,” the devs noted.
“If you mess it up and the teleport loops, you could end up in a bugged-out limbo of infinite warping… and crash everything.”
So yeah… no pressure.
TLDR; a *LOT* of experimentation and work went into building and getting the “underground feeling” right. The team had to work around these issues while preserving that feeling of seamless descent into a tense, unknown place. A lot of tricks were pulled to keep everything stable, immersive, and believable!
We hope this peek behind the curtain shows just how much care went into crafting these expeditions.
See you ithere, Survivors!