I started off design with three types of buildings; power plants to produce power, power lines to transport it and towers to shoot other buildings. The objective was to destroy your opponent's power plants and you were constrained by the amount of power you produced. We tested the game in one evening and it showed enough promise to start development.
Soon though, we noticed that we often didn't use up all our power, or that we used it on things we didn't need. So we added the power storage. The added advantage of this was that players could save up to do something big, like an attack rush or building a power plant. The power storage also is a power source, which means they can power your attacks even if the line to your power plants is cut off.
The next thing we ran into was that the player who took the first turn had a big advantage over the other player. And while it's impossible to fully equalise the start for both players, this was too big a difference. Our solution was to make power plants ramp up slowly, so they now take five turns to reach their max output. This also fixed the problem that building an extra power plant was too much of a sudden advantage.
But even with that adjustment, we found that rushing your enemy quickly became a dominant strategy for all players. Compensating for that was quite counter-intuitive. Mostly, you want to stimulate attack, to prevent the game from becoming stale. But we needed to reward players who were willing to think their attacks through some more. So we added a penalty for building more than two squares from a power plant or a storage.
And then there were two things we decided not to do. First, we did not decrease the power penalty if multiple power lines lead to one point. There were too many special cases to make that mechanic intuitive enough to use. The second, much tougher, decision was not to divide the available power if a player's grid has multiple parts with power sources. So you can use all your power at any point connected to a power plant or power storage, even though this is counterintuitive for many players when they first play Powargrid. Dividing the power would require a lot of extra mental bookkeeping and a lot of extra unfun actions for players, mainly because you'd have to assign all leftover power to separate storages at the end of a turn. And that runs against our wish to make the game mostly about tactics and to keep it as simple as possible. So we chose a slightly steeper learning curve instead of a mechanic that would keep on bothering people every time they play.
After that, we introduced another building to the game: the lightning cannon. We were reluctant to do so, since we want to minimise the base complexity of the game, while maximising the emergent complexity. However, we decided that a different option for shooting was needed to keep the game varied and interesting. It turned out to be a good way to reach through defences and damage power plants from afar.
With all that, there was one last issue to tackle. With the higher build cost with distance from power sources, the game ended up in a stalemate too easily (quite a seesaw experience). Michiel came with the solution: overcharge, which doubles a power plant's output, but also damages it each turn. It can't be turned off, so you lose that power plant eventually. Overcharge is good for sudden attacks and last ditch defence efforts. This adds a nice element of unpredictability. We knew this was the right track when we realised how much complexity overcharge added to AI design. Both deciding when to overcharge and taking into account that your opponent can do the same is hard. But more on AIs in a later post.
That sums up the system design for Powargrid. It's been quite a struggle to create both intuitive and easy to learn gameplay and enough emergent complexity to keep the game interesting in the long run. We think we succeeded, but we'd love to hear your opinion on the matter.
Thanks for reading. Next time, I'll discuss the look of the game. Or maybe Michiel will have some things to say... In the meantime, check out the new build. It's got music and multiplayer!