That card should be named something like "Marginally Bigger Battle" if that is how you play it. I thought it went down like this: I attack all your zones with attackers, then your defenders can defend from all attacked zones, and the leftover damage is applied to the attacked zone, which is all of them, so if I hit for 10 power and you have 8HP of defenders, I would do 2 damage to each zone since that attack was against each zone. You're telling me that I do 2 damage total and assign it to the attacked zones? Man man man man man…
In inventing how I thought this card was supposed to work, I looked at For Ulthuan! "Play at the beginning of your battlefield phase. Action: Your attacking units may attack two enemy zones this turn. (Declare which units are attacking which zone when you declare attackers.)"
For Ulthuan looks like a card where you would have to split the damage because you have to split the attacking units. In my mind, the fact that there is no split in All Out War means that they all attack each zone… But now that I look at All Out War it looks like the attack targets all zones, there are not three different attacks… But I would add that there is no precedent for this type of wording. I'm starting to get confused.
All Out War: "Play at the beginning of your Battlefield phase. Action: When you declare an attack against target opponent, that attack is against all of that opponent's non-burning zones. Defending opponent may declare defenders from all of his non-burning zones. This effect lasts until the end of the phase."
If you are correct (which is likely), I'm not sure how this card is supposed to be used. In the case where my opponent has three zones unburned, but two of them are damaged, and I could take them both out with one attack if I have enough power, this is a good card to play. Otherwise, it's almost always strictly better to throw a bunch of damage at one zone. I thought this card was supposed to be a meaningful alternative to Muster for War since you could seriously pummel the opponent with one attack, an attack you are forgoing to play Muster for War.