Reached Top 50 with Mecha'thun Warrior with 78% win-rate (21-6). By far the best deck in game for ladder. It just beats everything.
Your general combo and win condition is draw your whole deck and have in your hand Mecha'thun Malygos Whirlwind The Boomship and 2x Inner Rage (You can also have one more minion in your hand that has 6 or less health so it can die to whirlwind). You play The Boomship that summons Malygos and Mecha'thun. You Inner Rage Mecha'thun for 6 damage and Malygos for another 6 damage. That allows you to kill both minions with Whirlwind because with Malygos +5 spell power it does 6 damage aoe and that's how you do the combo and you win the game.
Not all your games will be this your condition tough. For example lets assume you play vs warrior and their Hecklebot hits your Malygos. You can still win pretty easily. To do that you do your combo with The Boomship that summons your Mecha'thun and you Shield Slam your Mecha'thun. Another trick you need to do vs warriors because some of them run Unseen Saboteur is if you are on coin always keep The Coin and Shield Slam so you have more chances of not hit your The Boomship and if it hits one of your combo pieces you do your combo with Shield Slam if it hits Shield Slam you do your full combo. If tough Hecklebot hits your Mecha'thun just go next this happens rarely and its the same thing like playing control warrior mirrors and one Hecklebot hits anothers Archivist Elysiana you just go next game.
Against aggro decks most of the times you don't win with your combo so use Inner Rage and Whirlwind alone or in combination with Malygos as extra removal and aoe. Always try to remove enemy minions with the removal you have first and use them if needed , because there is always a small chance you need your full combo to win the game. That's why i believe this deck is better against aggro and people don't tend to understand that , because they think it's a combo deck , but vs aggro is just a control deck with extra removal.
Against rogue your priority is to find weapon removals and aoe. Weapons Project is always a keep. Harrison Jones if you dont have Weapons Project or if you are on coin is always a keep even if you have Weapons Project. Warpath is always a keep. Town Crier is always a keep. Brawl is almost always a keep. Dr. Boom, Mad Genius is a keep if you are on coin and you have weapon removal and aoe. Slam is rarely a keep. Shield Slam is sometimes a keep. If you have the coin Dyn-o-matic is most of times a keep.
Against priest keep Brawl and Malygos Whirlwind. Most of priest play Chef Nomi and they bounce him back with Seance so they can play triple Chef Nomi. Brawl clears first 2 and Malygos Whirlwind the last one so they can actually win. Other than that always keep Dr. Boom, Mad Genius Town Crier and sometimes Acolyte of Pain.
Against warrior always keep Mecha'thun so they cant hit him with Hecklebot , unless you know they don't play Hecklebot. Always keep Dr. Boom, Mad Genius and Town Crier. Always keep The Coin untill you do your combo , if you have it , so their Unseen Saboteur has less chances to hit The Boomship.
**Omega Devastator at 4 is a good play most of the times unless maybe if you play against mage. Don't wait to get the full value of your cards your main priority is to dumb your hand and draw your deck so you can win. Use Harrison Jones in combination with Weapons Project so you can draw 3 cards , use Acolyte of Pain in combination with Warpath so you can draw 3 cards again. If you have all your combo in your hand you can overdraw so you don't need to waste turns and mana in cards you need to dump anyway**
SPECIALIST FORMAT :
This is your Primary deck. It can beat almost anything (except mages). You play this against rogues and aggro decks.
This is your secondary deck. Even tough the first deck can beat easily warriors this is used because most of warriors play combo disruptions cards at their side decks so they can deal with combo decks , but they cant win this unless their Hecklebot hit your Mecha'thun (which you should keep in mulligan if you have it).
If you believe or you know you gonna face almost 0 mages and lots of hunters this the the other tertiary deck that beats hunters.
In my opinion the anti-mage tertiary deck is better because you can beat hunters with your primary deck but against mages you don't have a chance.