Hearthpwn

[CAUTION] I got legend on April, so this deck might be out-of-meta right now. I can't play due to final exams. Feel free to change whatever.

Mulligan:

Rogue: Weapons Project, Acolyte of Pain,Shield Slam
Warrior: Archivist Elysiana, Dr. Boom, Mad Genius,Baleful Banker
Druid: Warpath , Acolyte of Pain , Eternium Rover 
Shaman: Warpath , Brawl  , Eternium Rover  
Mage: Weapons Project, Shield Slam, Acolyte of Pain 
Priest:  Acolyte of Pain, Shield Block, Shield Slam 
Paladin: Harrison Jones ,  Dr. Boom, Mad Genius, Acolyte of Pain
Hunter: Warpath , Acolyte of Pain , Eternium Rover 
Warlock: Same as druid, and hunter Warpath , Acolyte of Pain , Eternium Rover 

Little guide for matchups: 

Warlock, paladin and hunter: You need to mulligan as aggro, you will win most zoo and secret paladins, and will struggle against bomb hunters; you might consider changing Hecklebot  and put Spellbreaker if you feel pretty hard to win the last ones. 

They aren't aggro?

Free win against control warlocks, just try to draw for shield slam, if the 8-8 doesnt kill you, nothing will. Against mech control hunters and paladins... Not impossible, not easy. They dont have burst, save your Brawl to the limit.(consider to add Spellbreaker here too)

Mage:Too much things to kill. We use Weapons Project  for killing the 8-8 giant with Shield Slam.   This is mandatory, if not, they will destroy it and put 2 8-8. Just try to survive till turn 10 where Omega Devastator can save the day

Shaman: If not murlocs, super easy. Nothing can't out value you. If murlocs, don't die. Thats why we mulligan as aggro.

Priest: They are very rare, but you can lose against miracle priest, you need to be ready with 2 Brawls and 2 omega devastators. 

Rogue: Ouf. This matchup is harder any time you aproach to legend, the skill is more valuable in this players. For the hard one, (Lackey tempo rogue) you need to kill Edwin VanCleef with Shield Slam. And save Brawl for the double legendarie, Supercollider helps a lot too. Against the other Rogues, you can kill their weapon 3 times, they can't do much. 

Druid: Kill all minions. Don't let them have more than 3 little minions, Warpath counters their Soul of the Forest. Try to use it only when this happens. If they play The Forest's Aid, you just need to Baron Geddon. Almost GG. 7 mana win the game. This match up ends when this happens or the board is clear and you have Dr. Boom, Mad Genius.

Oh! I almost forgot!

Warrior: Against bomb ones, you need to take the count of how many bombs you have in the deck, and use Archivist Elysiana  even if you have a lot of cards remaining. It can be worth it. This matchup is not easy, but if you manage to survive, you usually win. Against control mirror... Who Hecklebot into Archivist Elysiana wins, if this not happens. You win. Baleful Banker plus Archivist Elysiana, is too much. If the other warrior have some similar combo which allows him to double Elysiana... This will be a draw. A 40min infinite draw. The game will end whitout no one diying. Literally. The game ends after a large number of turns, look at this: 
This was a draw, I was inmortal! But this was a draw. It was so sad. Try to get the most greedy things for Elysianna in this matchups.

This deck is good! But you also need to know how to play with him; learn the meta and play around it. And sorry for bad english