Hearthpwn

Requires a literal perfect hand of the Deathlord plus both Divine Spirit by Turn 6. If you play the Deathlord earlier he will be taken down by minor minions, or combo with a spell and then minions. 

Basically, if you don't have the above by Turn 6, concede and try again because Turn 7 is fatal. After 2 hours though, I'm beginning to lean towards this deck is statistically improbable. 

Managed it about 30 minutes after posting. Was extremely lucky with the minions and what Nef brought out, then once the cards started rolling in, yea very lucky. I guess if you haven't got another deck with the necessary cards, this method is probably your only option.

I didn't have Force-Tank MAX, swapped them out for Sea Giant and Kel'Thuzad. Also only put in one War Golem alongside an Ancient of War. However I see that both of those changes are a little redundant as you mainly field the larger cards through the Pile On! Ability.

First time I've managed a first-go. RNGeesus and Deck must have been good to me.

Lightening Storm.

Lightening Storm.

Lightening Storm.

Every time you get a decent presence of minions, forget about it. 2 hours and then some with this deck, probably needs adjustment because you can't keep up with Thaddius' minion spam. Assuming they paywalled this one. Not pulling the perfect RNG needed.

Edit: Managed it 5 minutes later, literally needed the perfect RNG. Thaddius only brought out 2 monsters, I had the counters with support Cleric to up the AP/HP on a Nerubian spawn, followed with a cleric support on a Shen, and two Mind Blasts. Anything else is going to be bloody long, as above.

Managed it on the second go! Just go all out, and used cleave and a combo if the tank card came around. The Nightblade is what won it thanks to the boss special.

Don't understand how people managed to defeat her on the first match with this deck. 

Been four hours here on Normal, must have the worst RNG in the known universe or something else is at play. I'm getting those 8/8 monsters thrown in alongside other minions that aren't the Creepers to form the blockade.

I'm having to down vote this one, I'd say something has changed in the AI playing certain cards which now makes this build redundant. It seems to be on the third turn Shade of Naxx followed by the Ooze Shield on the following turn. This deck doesn't have the numbers to bust through two shields and then the Naxx before it becomes too powerful, unless you happen to have that 1 in 1 million RNG chance that everyone else here seems to have gotten. 

I'll give it a go for another hour, then I'm off to find a deck that might actually work.