I have smoe questions about those two abilities.

1) For example Dark Archon and Zealot are attacked by Siege Tank and a Marine. Siege tank and Zealot are in frontline and Siege Tank uses Siege Mode card to destroy both Dark Archon and Zealot. Dark Archon uses Mind Control. So after fight there are surviving terran Marin and Mind Controlled Sige Tank. Does the attacker or the defender(because Siege Tank was just seized) have to retreat?

2) What happens if protos player plays Feedback and terran player plays EMP shockwave in the same skirmish? Is Feedback canceled or it depends on who is the attacker?

I'm thinking that since there are still defenders surviving the attack, the attacker must retreat. This would have been the case whether or not mind control had been involved given that the marine survived.

Also, with regards to the EMP shockwave and Feedback interaction, On page 38 of the base game rules, Cancel effects are resolved before all other abilities. In the case of both abilities cancelling, I think it resorts to Attacker first and then Defender 2nd. So it would probably depend on which side is attacking since they both have cancelling. That would be my opinion.

To 1) Mind control is applied before casualties for splash damage are removed (you could also use the Siege Tank as casualty for its own spash damage). Attacker must retreat.

To 2) If only one side plays a cancel card, it always applies (right unit needed of course). In case EMP vs Feedback, only the attacker's card is executed.

So I submitted the feedback vs EMP question to Corey and here's the ruling:

Question: What happens if a protoss player plays Feedback and a terran player plays EMP shockwave in the same skirmish? Would the Feedback be cancelled or would it depend on who is the attacker?

Responce: "Since the "Cancel" part abilities are resolved first, EMP shockwave would cancel feedback. The Cancel part of feedback can only be resolved if the rest of the card has been resolved."

So its like the EMP trumps the Feedback. Because the feedback has a condition that first has to be met, the EMP cancels the feedback outright.

That is good to hear as Terran player. Another mystery solved.

Shadowsword said:

Yay, that's almost as funny as casting "Spawn Broodling" on Siege Tanks, or dropping Zerglings nearby!

...however, keeping the Siege Tanks gives you a +2 support unit, and your opponent is reduced to maximally 2 Siege Tanks.