When I first learned about Core Values, the upcoming expansion to factory automation game Satisfactory, I didn't grasp the scale of the challenge developer Coffee Stain had set themselves. 'So, the game is set underground now?' I thought. 'I'll just stick up some more lights and make the same factory I always have.' Yet, as I covered yesterday, that won't be possible. For a start because you'll need to use new logistics tools to connect your factory buildings – conveyor belts aren't gone, but they're nowhere near as useful as they once were.

Another major difference, though, is a design problem for the developers: how to make a perfectly-sized cave.

In Satisfactory, the world is a large sandbox crafted by the designers at Coffee Stain. While there are a few maps to pick from, they don't use procedural generation or the like to vary them between playthroughs. When you start a game, coal, iron, and copper deposits will all be in the same places. The level designers' hand is making sure that your starting resources are all within reach as you unlock the early game tech tree. After all, before you've got conveyor belts and storage lockers to transport and hold your resources, you have to sprint between deposits filling your inventory with loose rocks and carry them back to your hub to refine them into usable materials. If the deposits are too far apart, then it would make for a needlessly dull bit of ferrying.

As you unlock later technologies, such as the mining drills, refining stations, and component assemblers, you fill the space between ore deposits and with a sprawling factory floor of interconnected machines. Being a largely untouched alien world, you're free to spread your factory out wide, stack it tall, or a mixture of the two. Space is virtually unlimited.

This is the key challenge for players in Core Values: your factories now need to fit in a box.

As game director Emmet Burke touched on in my other piece, space will be a big constraint for players, but it's also been a constraint for the designers. "We want to be very careful how much space we allow for different players, because you still want to have the cave feeling," he tells me. "You want to have the little tunnels to explore, but you want to make sure there's always enough areas that if people want to unleash their creativity, they have the space to do that, but then you don't want to just give them a big box [where they can] just build whatever they want. Level design was enormous here."

While thought went into the maps in Satisfactory's base game, the challenge in Core Values is that the developers need to know how players are likely to layout a factory that exploits the resources in the cave, so they can predict how much space they will eventually need. "We are essentially always testing our factory layers across the entire biome," Burke explains, saying they need to factor in what technologies a player will have at different stages of progression through the tech tree, what resources they will have available and in what quantities, and then map out different factory styles to see if they'll fit in the cave.

"I always see it like a triangle," art director Torsten Gunst tells me. "We have the cave environment and the size and shape, but we also have the amount of factories you need, how expensive the recipes are, and the size of the buildings." By keeping an eye on those factors and making tweaks where needed, they can end up with a unique cave shape that can also contain the optimised factory that best exploits the resources you find within it.

The developers wouldn't say what any of the new logistics tools are, but I suspect the constrictive nature of the cave will push you to embrace them over old tools. I mean, I say I suspect that, but producer Julio Mendez effectively tells me that's the case when he says "I don't want to spoil anything out right, but there will be challenges that come from the specific new environment that we have."

So there is a great deal of planning on thought going into constructing Core Values' map, ensuring that its caves are varied and practical – not too small to contain the factories you need to build, but not so large that they don't challenge you. Still, after all that, Coffee Stain have to remember that Satisfactory players are crafty buggers. "People will find recipes that we didn't even think of," Burke says. "We have a vision of how this is going to be balanced and then... We can't test every single combination."

Then there are the players who maybe aren't so crafty, the ones who don't know how to perfectly optimise the flow rate of a factory to ensure no machine is left starved of resources or unable to eject what it's produced because the conveyor belt it's linked to is full. Burke says they have a rule of thumb for players like, well, me: "We just give them an extra like 25% cave space for the ones who want to build bigger."

So, yes, there is a great deal of thought that goes into making the perfectly-sized cave. Then they add 25% for the players like me who struggle to think inside the box.

Travel and accommodation to Gamescom was provided by the conference organisers.