While developing Battle Mode, we tried some things that ended up not quite working. We tried a bunch of different Health values. We tried a mode where the Reality Stone transformed cards in your hand before each game. Developing in Unity, it was super easy to jump in and try out wild new ideas.
Early on, we saw players playing no cards in games 1 and 2 to scout their opponent’s decks, paying a couple of Health to gain critical information. Back then, Heath Pools were much larger, so a couple Health meant very little, and as we lowered total Health, those first couple games could make all the difference.
Battle Mode takes about 20 minutes, but in early playtests between two players who retreat back and forth for a series of one Health games, it took much longer. To keep Battles around 20 minutes, we added “High Stakes Rounds,” which kick in starting on Round 5. High Stakes Rounds start with the stakes at two Damage, so it’s much more deadly.
Another thing we learned was that if players took some early beats and were one game away from running out of Health, they could SNAP with impunity since it doesn’t matter if they end up at zero or negative six; death is death. We wanted to reward players for early victories, so now, you cannot deal more damage than you have Health remaining. It means that coming from behind is possible, but those early victories aren’t irrelevant. And the “bluffing” aspect of the Snap remains intact, since your opponent cannot risk health they do not have.
Source: Unity Technologies Blog