Hearthpwn

Shadow Visions- This card is pure tech, search for that extra kill card in whatever fashion you need. Or finish the combo early.

Power Word: Shield- Card draw and synergy with any creature, a lot more cards from Acolyte of Pain.

Shadow Word: Pain- This card is self-explanatory just play it smart, don't knock off a Snowflipper Penguin just because it's on the board. Use this for stopping small mechanics based creatures (i.e. Sorcerer's Apprentice) or that murloc you know the paladin will buff next turn to a 4 power.

Shadow Word: Death- Again self-explanatory, though not as much finesse is need as it's smaller counterpart there still requires a bit of control. If you are still well out of death range, it may be better to use a different option, like trading minions. Just read the board and play smart.

Mass Hysteria- Fun board damaging card, can clear their side of the board, can also be used to passively kill your Carnivorous Cube for combos.

Holy Nova- Board wipe, though a bit on the weak side, this can take care of small minion armies and as a bonus can keep your minions healed.

Psychic Scream- Board clear, deck manipulation, curve destruction, and all around good shenanigans. Not a card you want to play with power minions on your side but it can save you from an untimely death.

Vivid Nightmare- Copy mechanic, this is part of the win condition and also makes for some fun options. The minion comes in damaged so it is possible to heal it back to full.

Bloodmage Thalnos- Simply the best of all worlds here, card draw spell damage and an early game minion. Also draws out kill cards fast.

Sand Drudge- With the number of spells in this deck this allows you to get free taunt minions without the cost of extra mana crystals or deathrattles.

Loot Hoarder- Card draw and a nice little trade, gotta get to that combo faster!

Auchenai Phantasm- Battlecry minion that creates the kill conditions without the drawback of not being able to heal yourself after the turn it's played.

Carnivorous Cube- Cube priest a new thing?! Copy that Clockwork Automaton, or Prophet Velen, let it die for a quick exponential growth to damage. (Trick here use Vivid Nightmare and Spirit Lash to set up an OTK).

Acolyte of Pain- Card draw, and with the healing mechanic from priest you can potentially use him for a few turns.

Clockwork Automaton- Mini Prophet Velen, though it's stats are mid-range it is outside of direct kill from mirror matches. This minion works as a backup or replacement for win conditions if Prophet Velen is done in.

Shadowreaper Anduin- This is your kill card, and it also lets you clear the board in the meantime. Play it before your Clockwork Automaton then unleash shadowy mayhem.

Control, control, patience. Stall your opponent with board clears trade and kill their minions, go for value always, use Loot Hoarder and Acolyte of Pain early as possible for card draw engine. Power Word: Shield, though its a good buff for your minions don't be afraid to play it on their minion if you can Power Word: Kill it. As with any deck that relies on card draw of this nature, watch your hand size it's quite easy to burn cards if you aren't careful.

Shadow Visions: this will more than likely be used to find more control, if this is in your opening hand be patient it isn't necessary to look for anything right away see how your opponent is playing and search around that, turn 5 search into a Holy Nova or a turn 9 search into a Psychic Scream this card is versatile. Generally you won't need this to find Vivid Nightmare but if you find that you have full control of the game and can set up an otk the next turn go for it.

The final plays will revolve around Clockwork Automaton being copied by Vivid Nightmare and/or Carnivorous Cube. Be wary, silence, polymorph, hex or theft mechanics can turn the tides quickly don't push the board unless you are certain you have time, play the cube too early and you can watch as you lose out on a double Automaton and sit with a 4/6.

Auchenai Phantasm- This is a technical kill card, with this and a few Clockwork Automatons, you can do serious amounts of damage with your hero power. But this is also a minion kill card as well. Be creative with it.

Last notes on the deck, go face as often as the board state allows you. It might seem illogical considering this is a combo deck, but the potential to set up a faster kill with the tools given is very high. Less health means easier combo.

Winning; Having tested at least the theory of this deck prior to Witchwood release I would like to point out a finding and as well show how this deck can either steamroll or OTK based on how it plays out.

Prophet Velen, Clockwork Automaton and the copies of them will cause your hero power to grow quickly.

Let us look at the basics: Lesser Heal
Prophet Velen makes this ability go from 2 -> 4
if we copy him his ability kicks in and once again buffs the hero power, though it does not check the base output of the hero power multiplying it again by double. It does, however, check the current power and doubles that instead.

For the sake of showing the improper math as well as the correct, I am putting the layout below even if it's redundant for some.

Incorrect math #1: this would be; 2 -> Velen 4 -> Copy 6 -> Copy 8 (the ability isn't adding the bonus continuously it is multiplying it) (2+2+2+2)
Incorrect math #2: this would be; 2 -> Velen 4 -> Copy 16 -> Copy 256 (this seems correct because the ability is doubling the effect but it isn't multiplying itself) (2x(2^4))
Correct Math: this would be; 2 -> Velen 4 -> Copy 8 -> Copy 16 (The effect is multiplying the current version) (2^4)