Try to play Coldlight Seer on Turn 3 (and/or Felfin Navigator on Turn 4) or as early as possible, so murlocs can survive Doom Lord Kazzak's Hellfire. Doom Lord Kazzak also has 2 Despicable Dreadlord and 1 Felfire Potion, but unless you get unlucky you should be able to buff your murlocs before his board clears.
If you don't have one of the cards you can replace it with Bloodlust. You could also replace Mana Tide Totem or Flametongue Totem with Bloodlust. Its winnable without Bloodlust, but it may help if you're having trouble.
Game Starts at 4:53