This deck is amazing. Reached rank 3 with it, and it has reached legend in the past. Great, cheap deck that almost anybody can create, also really fun!

Mulligan:

Fiery War Axe, Acolyte of Pain, Mad Bomber, Loot Hoarder, Ravaging Ghoul

Alternatively, Gnomish Inventor and Bloodhoof Brave can be kept depending on your curve and opponent.

Strategy:

Early game:

You want to draw as many cards as you can! Also, keep yourself alive! You can afford to be aggressive with this deck a lot of the time by slapping their face with some of your many early minions to knock their health down, because once they are at 20 points of health you can win at any moment! Of course there are times where you have to trade, this all depends on your hand and opponent. Kor'kron Elite is effective for punching down their health to put them in combo range. Bloodhoof Brave is good for stalling out the game. Save Execute for removing taunts or large threats. Especially taunts as they will completely counter your win condition. Try to use Battle Rage to draw at least 2 or 3 cards, as this will give you a huge swing in ability and greatly increase your chances of winning.

The win:

The cards you need to win the game are Charge, Raging Worgen and a combination of one or two (max two or else the worgen dies) Cruel Taskmaster and Inner Rage. Yea, its that simple. Some things to keep in mind: Charge + Worgen + 1 activator = 16 damage. With 2 activators, its 20 damage, which is the maximum this combo can do.

Other cards that are good in this deck:

Rampage, Frothing Berserker, Mortal Strike, Abusive Sergeant, even Grommash Hellscream

Despite these good replacements i prefer the original decklist. It may seem that getting a bigger combo is better but the 16 or 20 damage is often enough to finish your opponent, especially with the other instant-damage cards you have like Kor'kron Elite and Fiery War Axe, its not too difficult to push your opponent into combo range.

The beauty of this deck is how cheap and simple it is. Really good deck for beginners as it teaches you the mechanics of hearthstone, and how to play a specific decktype. Very fun and satisfying wins! Good luck