Hearthpwn

Intro

I've been playing this deck on ladder since Summoning Stone was available with LoE. I find it's extremely flexible in adapting to matchups. Whether on the offensive with Mad Scientist and Mana Wyrm or shutting their board down with Forgotten Torch Frostbolt and Mirror Image, Counterspell always acts as the core of this deck in ensuring the safety of your minions, specifically the Stone.

It's a tremendously fun deck to surprise your opponents with, and I'm continually amazed that it keeps working. The best part is how cheap it really is, compared to meta decks.

As of 12/29:

Mulligan

The mulligan really just depends on your opponent. However, you should always keep the following: Jeweled Scarab Mana Wyrm Mirror Image Counterspell Mad Scientist and at least 1 burn spell like Arcane Missiles or Frostbolt. Against slow/control decks, keeping Arcane Intellect is a good idea so you can draw into responses/fatal late game damage.

Play Style

It's really entirely situational and depends on your own intuition and experience. The deck is very flexible, especially with amazing tech cards like Jeweled Scarab and the secrets/control spells.

Always lean towards controlling the board, but don't forget that you have potentially 18+ damage sitting in your deck that you can throw at their face in one turn (2 Roaring Torches and 1 Fireball for 10 mana). Against control decks, just stall and draw cards and be sure to expend your Forgotten Torch when you can so that you can combo all your damage spells and burn them in one turn, so they can't Reno Jackson.

I've won plenty of matches with turn 6/7 fatal, using the turn 1/2 Mana Wyrm+Mirror Image combo, and ensuring continued damage with the turn 3 Counterspell and turn 5 Loatheb

Against aggro, play the classic mage. Use your hero power as often as possible instead of using actual spells. Only resort to spells from your hand when you absolutely need it, because you're losing your potential win condition. However, given the nature of aggro decks, you won't have much burn left in your deck by the end of their rush, so just hold out until you can Ragnaros the Firelord to put them on a fatal timer.

Key Combos

Mad Scientist into Counterspell into Loatheb or Summoning Stone or Ragnaros the Firelord

Oftentimes I find myself just slowing the tempo and managing the board until I can double Roaring Torch and Fireball their face, or stalling them into Flamestrike with Summoning Stone to clear their board and yield a giant minion like War Golem Obsidian Destroyer Stormwind Champion Dr. Boom et cetera...

Substitutes

Feel free to experiment with other legendaries to replace Ragnaros the Firelord and secrets like Ice Block to replace Mirror Entity or whatever other edits you want. However, keep in mind that this deck has 3 reliable win conditions: the 10-mana combo Fireball + 2 Roaring Torches, Ragnaros the Firelord, and value city Summoning Stone control combos.

Good Luck!!