The game basically revolves around you and your "opponent" trying to kill an enemy which has 95 health. If either player dies, then both players lose.
The enemy is setup to switch to each side so that your minions can attack it. On its turn, it can either power up its attack, attack each player, attack 3 random enemies or destroy a minion.
What's cool about this co-op mode is that the pre-built decks have a lot of cards which benefit both players. As a result, provided the other player knows what they are doing, you can actually setup some really nice combos. Unfortunately, this does depend on the other player knowing what they are doing - not always a guarantee in any co-op game.
Overall though, it was a really fun mode and I hope Blizzard bring it back at some point. Either way, I continue to be impressed with Tavern Brawl and how it changes up the games mechanics.
