Hunter and Mage were the hardest, rest I did within 2 tries of figuring out the condition.
Decks for the classes:
Druid: Jade Druid
Warlock: Renolock, emphasis on Deathrattles and Nzoth
Shaman: Token Jade Shaman. Jades still scale the same and you can just Bloodlust
after having a big board.
Paladin: Murloc Paladin, you can kill him before he does Frostmorne.
Warrior: Tempo Patron Warrior with lots of Deathrattles. Double Armorsmith to keep armor up in late game and double Frothing Berserker with a Faceless for the win condition. I think I ended up hitting for 80 damage in a turn to win. Don't have too much draw in this deck, I made that mistake initially and once I cut the draw it was a lot easier.
Mage: Elemental Mage with healing and secrets that I can cheat out with Mad Scientist. You really need to have a solid board of Elementals and Jaina DK played on time to win this (and of course survive the initial early game). If you stabilize with a solid board then you can generally win, the healing is insane.
Hunter: Reno Hunter with the only minions being two Stitches, Doomsayer and Reno Jackson. You really need all of these minions to win as well as the Hunter DK. For the Hunter DK, getting that lifesteal worm is a must.
Priest: Combo Inner Fire Priest from Wild. Once the Obliterates were out of the way I just made a massive minion and just pelted his face.
Rogue: Deathrattle Nzoth Rogue. Just played the most efficient, curve minions and you will win.