As our Canadian, Australian and Dutch players will have noticed, we recently made a big change to Combat Card’s MMR system, with the result that ‘normal’ battles have become much more challenging (there have been no changes to the Campaign battles, which are always fought against AI created decks).

Let’s explore the change, why we made it, and what we learned.



The change we made was to turn back on matchmaking against other player’s decks, as for the last few months – as part of our improvement works – the game has only been matching you against AI created decks.

To be ultra-clear, when you fight a battle the enemy deck is still being controlled by an AI, but now that AI is picking decks created by other humans to use against you. I’ve written about improving our AI before, and more on this in the future, but for now let’s stay focused on MMR.

Your MMR (Match Making Rating) score goes up when you win and down when you lose, and the game uses it to find decks built by other players with roughly the same score as you. By giving the AI the decks those players are using, we theoretically ensure every battle is fair. In reality, it is of course not as simple as that, with complicating factors – such as the fact that players swap which deck they’re using a lot – making it difficult to guarantee a perfect matchup.



We deal with this by giving each player’s MMR a ‘confidence value’, which is how certain the game is that the player really does have the correct MMR score. A low confidence will see your MMR jump around a lot as you win and lose battles, until it settles down and makes smaller changes as the system gets more confident that your score is roughly correct.

Interestingly, this confidence value is why the difficultly of battles has suddenly altered, not a problem with the MMR itself.

Firstly, we haven’t been looking for new players while we polish and improve the game, so most of our players have been playing for a long time now. As a result, they all have roughly the same MMR score, so the game finds it difficult to match players with a lower score against anyone specific (it has too many people with the same score to choose from).

Plus, because we just turned MMR back on, the game has no real confidence in anyone’s score, so it will take time for it to work out what everyone’s MMR should really be. Unfortunately, during that time the difficulty of each battle may vary wildly, as the system has to start from scratch with building confidence values.

In conclusion – our apologies for the upheaval, and thanks for your patience while it settles back down. On the plus side, at least these changes are for a good reason – a strong MMR system is essential for making the game fun to play over the long term, as it helps ensure battles are neither crushingly difficult or too easy.



One final area I’d like to discuss is that aside from improving how we work out and use MMR, we’ve also spotted that we need to communicate changes like this better.

We made a post to our Facebook page about the change, but obviously not everyone will see that, so we need to improve our in game news service so we can let players know about these sort of changes in advance of them happening.

Thanks to everyone who sent us feedback or comments on the MMR change. We may not be able to respond to them all, but we do read every comment. Discussions are underway here on how to improve the way we engage with you, the community, so any feedback or ideas on this are welcome!

Thanks for reading. As ever, you can get in touch with a comment below, mailing [email protected] or through our Facebook page.