Template:Corrupt the Waters strategy
Completing the quest is extremely trivial. There are many, many different cards with Battlecry you can use, and you only need 6 of them. Lackeys can also be used and make the quest progression even faster.
Once 
Heart of Vir'naal is unlocked, most of the Battlecry cards get a massive boost. Direct damage like 
Kobold Lackey and Weaponized Wasp are doubled, card generators like Swampqueen Hagatha and Barista Lynchen create twice as many cards, Siamat gets all 4 keywords, and so on. The onslaught of value these cards can bring in combination is used to close out the game.
non-stacking Battlecries
Cards with absolute effects like 
Reno Jackson and 
Platebreaker do not benefit from a 2nd activation. Nor do 
Tour Guide or 
Anonymous Informant since Hero Power and Secret cost are already reduced to 0 and this won't carry on to an additional usage. Spellward Jeweler also does not give any additional turns of protection to the hero. It also does not help 
Horde Operative since you can't have more than one copy of a secret in effect. There is also no benefit to weapon-destroying cards like 
Rustrot Viper since the first cry would already remove the objective. 
Chief Inspector and Steamcleaner also don't double up, since all the secrets/cards are already vanished by the time of the 2nd cry. It also doesn't help 
Grumble, Worldshaker since it has already removed all cards to hand.
About the only benefit to these cards is that it puts extra copies of these into the "battlecries used" pool which Shudderwock draws upon - this means when Shudderwock randomly runs through every battlecry a player has ever used, the extra copies increase the odds of it being called early on in the order.
This template contains Strategy content for these cards.
Remember that this is just an archived content of Strategy section that was supposed to be removed following the decision in Hearthstone Wiki:Project 13. It's up to you to review the content and keep them for a project in the future. Details to follow soon, once Project 13 is completed.