Hearthpwn

Strategy:

Your object is to build a huge Stoneskin Gargoyle. The Murlocs will ignore your minions, so this object is possible.

Try to summon a Gargoyle as soon as possible, then give him all the Health-increases, then Divine Spirit. In my opinion, 16~20 is ok. Then, give him the taunt by Sunfury Protector, and enjoy the mulocs' committed suicide. Giantfin does not have any removal, so the Gargoyle is immortal xD.

The problem is how to survive until your Gargoyle-building is completed. Use Silence on Murloc Warleader, or Tidecaller if it's big. Use Power word Glory on the tiny Murlocs, remember to let them alive, and 2 Lightwell will help you survive too. Use Holy Smite for the Murloc Tidecaller at early, and Explosive Sheep and Holy Nova to clear board when your Gargoyle's still tiny. Flash Heal to your hero or your Gargoyle if it's taunted but does not have much HP yet.

Loot Hoarder and Novice Engineer will help you draw cards.

You can replace the Inner Fire by Wild Pyromancer to help you with clearing at early and keep you alive. Your Gargoyle is immortal, so his ATK is not really important.

1 last thing: The Gargoyle-building is more important than saving your HP (of course your HP must be at least 1). When you can be still alive in the next turn, let them attack. Giantfin does not have any removal or Damage-Spell, so 1 HP and a huge Gargoyle are enough for the win.