Generating the world of Sunless Skies
by Liam Welton
When we started working on Sunless Sea, there weren’t many games that attempted to blend exploration of a randomised playspace with interactive storytelling. In the process of making that game, we learned a lot about the sort of experiences we wanted to create, and also a few that we would perhaps want to avoid in future.
Sunless Skies presents an opportunity to refine the formula we created in Sunless Sea. In order to make sure the sequel improves upon the first game, we’re breaking the systems down, analysing what worked well, what worked less well, and testing new approaches.
One area we’ve been focusing on is the shape and layout of the world itself. In Sunless Sea, the Neath is a vast ocean bounded on two sides by a cavern wall. When a player starts a new captain, we generate a map by shuffling collections of tiles and placing them within predefined areas.
Some tiles are always fixed in the same location (the grey ones), but most move within a predefined region (red, blue, yellow, orange & purple). Restricting their placement meant we could balance the difficulty. Anything in the region surrounding London would be for the early to mid-game, whereas the far eastern area of the map would be late-game content.
One of the core loops in Sunless Sea is setting out from the known location of the Southern Archipelago towards unknown and increasingly unusual locations. You set off and explore, discover new areas of the map, and return to London.
There are two halves to that journey – outwards toward the unknown, and homewards towards safety. When we sat down to analyse what was successful about this loop, we realised that the exploration of the unknown was much more enticing than the return journey. Returning was essential, obviously, and much of the tension and emergent storytelling in Sunless Sea comes from those moments when you limp back to London after over-stretching yourself and barely surviving. However, after you’ve been playing the game for 20+ hours, those journeys backwards across the entire map can begin to take their toll.
For Sunless Skies, we want to keep this core loop, but reduce the amount of time spent traversing explored territories. In order to do this, there is no one place your captain can call home. Instead, you will find several large ports throughout the game. Upgrading your weapons and ships, picking up crew and passengers, trading in valuable goods – all of these can be done in any of these large ports.
These major ports act as the points around which we will build the entire world. Each sits in the centre of a region of space, surrounded by other settlements and discoveries. The central ports will remain a fixed location in each game, but the surrounding areas will be randomised within a radius around that central point. In one game, the small colony of amphibian potters might be on the outer north-westerly rim of the region, in the next they are closer in to the south-east, providing a trading opportunity unique to that captain.
The tension created by having to struggle back to a major port will still be there, and the threat of overreaching and dying in the cold, uncaring vastness of space will be just as present as it was in Sunless Sea. But your journeys will be shorter and more varied, and the new opportunities awaiting you in ports even more tantalizing. For those brave enough to leave the safety of their known region, there will be other, perhaps greater, civilisations to explore in adjacent regions.（source：gamasutra）