Hearthpwn

I don't have the quest, therefore no Megafin, but I still wanted to play something with murlocs and quick & heavy aggro. Can easily run off the board by turn 4, when Finja becomes available. Can easily deal with very fast decks like Quest Rogue, Pirate Warrior and Facehunter.

General Notes

Play a very aggressive curve, but stage your murlocs' in waves with the Finishers if you can.

Possible Openers

With coin, it opens with Juggler or Primalfin or Tidecaller. Without coin, it's the usual any 1-drop, then Juggler or Primalfin. So on, there's a shit-ton of options.

Mulligan

It generally depends on your opponent. For QR, try to mulligan into Juggler, Primalfin and summoner stuff, you need a very fast game here. For PW, go for the Golakkas. For Taunt Warrior, Earth Shock is very useful to get past early, big taunts.

Generally, you want to mulligan into a usable 1-2-3-drop, I usually discard everything if I don't have Juggler, Primalfin and go from there.

Weak Points

Taunt Warriors are a problem if you can't beat their curve. Control Mage & Paladin can also be a pain in the ass, if you don't pace yourself for mid / late game. Finishers & Megasaur, Finja kill > Megasaur & Flametongue works wonders there to turn the table and/or push face.