There is an order of attack in the animations, but it seems to change and some units even seem to attack together. If I'm not mistaken, its something like:

1) Ground Bombardment: Defender (D) 

2) Ground Bombardment: Attacker (A)

3) Infantry: (D)

4) Infantry: (A)

5) Armor: (D)

6) Armor: (A)

7) Air: (D)

8) Air: (A)

But this all seems relative depending on the composition of both armies (not merely skipped if something isn't present). It's unclear to me if certain units have target priorities (Bonus vs) or if once killed (shaded in the animation) if this affects their combat stats, damage, etc.

It looks as if Bombardment spreads damage evenly, but I'm not sure.

Maybe some of this doesn't matter in the grand scheme of things (just keep hitting "Blitz" until you win) but I like to understand how systems work. It seems like you could better design your compositions if some of this was more clear.

Thanks, Groo. I read the dev diary you posted.

It's definitely not the finished product we know now, but it does provide some insights.

From the article:

"The battle is divided into rounds, during which troops will attack each other. We consider 1 stack per type in terms of resolution and not each unit individually. Each type of troop is going to deal damage to all types of troops in the opposing side. The number of rounds will vary depending on the tactical decision taken by the attacker, meaning a ground battle could last more or less turns based on that. When a stack of units attacks another stacks, it generates X damages. X is the sum of damages computed for each units of the stack. A unit deals damage, randomly between its min and max damage values."

I'm not clear what they mean by "stack" exactly, but then they go on to say that stacks attack other stacks, and also each type of troop deals damage to all types of troops on the other side. Almost seems like it is a die roll on what unit/stack will attack which unit on the other side. So, maybe you have a bunch of tanks, but you could roll unlucky and those tanks end up attacking other tanks or planes instead of the infantry, so only a few of them actually get their "Vs Infantry" bonus?