Written by the lead designer Adam Španěl

ONLINE TESTING & FINAL BALANCING

We tested Drillers with our awesome community online in our internal testing system, having finished over 1400 games in total. This gave us a plenty of data to work with, allowing us to adjust values accordingly. Not only was this great fun, but we arrived at a balance I feel very confident about.

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THE TESTING PROCESS

A testing wave is always a big and intensive event. It usually runs for about a month. With Drillers, we had one preliminary smaller wave, and a bigger second wave. Those seasons were the core of the development of the game where the most major changes were tested, and most of the balancing was done during this time.
We had weekly iterations, which we created based on 4 main pillars:

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1. The stats

‍We balanced the card costs and properties mostly based on the raw numbers. In Drillers, it was a bit complicated by the fact that a higher score doesn’t necessarily mean better performance, because Drillers is a game of variable number of turns. Scoring 150 in 9 turns is an excellent result, but scoring 150 in 14 turns is not so great. We had to take this into account. We focused more on relative score within a game and card efficiency. The other important stat was the card popularity, or how often was it bought. One of the main goals for the shop was to not have cards that you don’t want to buy, and this was really useful. Even a well balanced card needed reworking if players simply didn’t want to buy it.

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2. The player feedback

This was the subjective part of the input and often very detailed. We were asking our testers which cards felt strong or weak, or what was the reason the winner won the game. We never made changes in isolation, it always had to be considered alongside the data.

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3. Game replays

I spent many sleepless nights clicking through replays of the outlier games, and the regular ones as well, trying to understand where the feedback and stats are coming from.

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4. Expert insight

Mucube, our community manager, was a big part of this as well. He is a very strong player, and long-time friend and digital tester for CGE. He mastered the game and put in the reps to have a really strong understanding of the game and balance, and produced a number of detailed deep dives into the balance of the game.

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SOMETIMES BALANCE ISN'T ENOUGH

The perfect situation, of course, is when the data, the feedback, and the expert opinion all line up. But, the reality was that more often than not, it wasn’t as aligned.

One particularly interesting example is Antigravity Drive.
The ability looks super unique and strong: “You just teleport anywhere? For free? What’s the catch?”
This card was notoriously flagged as OP, with many players saying that the winner won “just because of this card” and that it “feels like cheating”. But the hard data simply didn’t support this.
What’s interesting about this card is that it actually is weaker than, say, 6 movements. With standard movement, you can go down and back up with a single card and collect minerals on your way up. None of these is possible with the Antigravity Drive.
But the feedback regarding this card was so notorious, that we had to keep making it more expensive, so it ended up on the slightly weaker side by data, and slightly stronger side by feel. Sometimes, even if a card is balanced, it is more important that it “feels” balanced.

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TWEAKING THE NUMBERS

Digital testing was also great for getting the starting resources just right. Here, it was a bit simpler and more straightforward: we tuned the numbers until the winrate for each position was more or less equal.

There are many mechanics where setting just the correct price was quite a journey, and it is like balancing on a knife’s edge.

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We hope you enjoyed this final part and the entire series of Under the Surface: The Design Journey of Drillers! Thank you all for being with us on this journey. We really appreciate all the support you have given us.

If you haven’t had the chance to read the previous two parts, here are the links:
Under the Surface: The Design Journey of Drillers PART 1
Under the Surface: The Design Journey of Drillers PART 2

We're looking forward to bringing you more articles in the future. By the way, keep an eye out for our official "How to Play" video coming this July, so stay tuned!
To make sure you're notified once we release something new, subscribe to Drillers on BGG.

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