For Beyond Sol we want a solid grand strategy experience in both single player and multiplayer that is theoretically unending, which means the game has no time limit and no game over screen - the game can run forever. In multiplayer you have other human opponents who can act in their own interests and react to what you are doing giving you a constant threat to manage, but if you play alone we need to provide you with interesting AI opponents. So we created sophisticated AI players that will be present in both single player and multiplayer games, and these AIs are designed to be ruthless and they will try to become the dominant power in the solar system. While creating this kind of un-ending conflict system, we encountered a barrier with testing the game world - time.
The Problem
We created a world where city states grow and fight each other over resources, and new cities show up in unclaimed space over the course of the game. Mighty empires rise and fall at the hands of coalitions of their neighboring rivals and this cycle appears to go on indefinitely in our single-player and multiplayer play-tests. We started asking ourselves some interesting questions about the long term outcome of the game. How long does this cycle last? Would a single city ever conquer all the others? How big can these cities get? Does our game balance hold after dozens and hundreds of hours? What kind of bugs would we encounter in the late game? Unfortunately we don’t have the manpower or time to run the game for twenty days to just do one test. This would take weeks to iterate on balance and our Early Access launches at the end of the month.
The Solution
We needed a way to play the game at an accelerated pace so we could test days worth of progress within hours so we created a debug option that allows us to run the game logic faster than normal. After testing this new debug tool we discovered we could run the game x10 faster than normal without performance problems. So on the first day, we launched a new game running at x10 speed and let it run overnight to see what happened to the cities in the later stages of the game. We were very excited to see the results because we had never been able to see further than about 18 hours of play before.
The next day we discovered the city AI was broken somehow (they stopped building and attacking), but we couldn’t tell at what point they got broken. We were disappointed with the results and the lack of critical information we got out of it and realized that just running the simulation would not be enough because we would need to observe the simulation throughout the whole playthrough but it is not practical to have someone watch the game running this simulation for 20 or more real hours.
We had recently redesigned the map UI to support a zoom mode that allowed us to view the whole solar system on the screen and it occurred to us that if we could capture a screenshot on a regular interval we could simply review the screenshots to see how each city developed and expanded. We ran multiple simulations and found some major bugs in our AI that you would only encounter beyond 20 hours of play where they would get stuck trying to build something or were not replenishing their fleets so they would lose their next war and so on. After a week of this kind of debugging we managed to get the AI cities to play for 20 days or more without breaking. We haven’t tested beyond this point because we are always making changes to the code and need to start new tests every night, so we don’t actually know how long the world simulation can go on for.
It has been interesting watching each new playtest recording over the past few weeks, sort of like watching the recap screen in Civilization games where you see the equivalent of an animated GIF of the world map and you see empires rise and fall. We are really happy with the results so far because the world is incredibly dynamic so sometimes one power will emerge early on and take out most of the solar system, and other times many competing powers will fight endless wars trying to get on top. Often the biggest power mid game will be destroyed in the late game because the other factions will gang up on him and take him out.
We can’t wait to get more people playing the game and sharing stories about how their world played out!
