Theme:

Defensive, luring, drowning, maxing out the "body of water" space and dominating the field with big sea monsters to chase down an avatar for the win

Key openers:

Defensive play is essential in the early game, keep a hold of defensive sites that can limit movement from more aggro decks [[troll bridge]], [[thin ice]] and sites that can provide you blockers (bring on the frogs).

You want to make sure you've got some smaller minions in hand, like [[shellycoat]] for effective blockers. And ideally you start or top deck some ramp through [[mix aqua]] or [[aquamarine core]] or [[overflow]] to reach those big minions earlier than turn 7. These are still useful later in the game, so don't play before you need them in case of removal. (Also I don't recommend playing the Island Leviathan too soon but you still want it in a good forward position, so having it in hand is a good idea for when the right moment arises)

Strategy:

Defensive
Flood
Drown
Big monsters <3

Match-Ups:

Does pretty well against faster aggro, majorly slows them down

Holds it's own, although a long game, against magic control (archimago etc) but can be tough to get that wincon draw that gets around lower power decks

I've yet to play a mirror match, not sure how it will hold up against other defensive decks

Useful:

Use spells like [[riptide]] on your own things if it gets them to where you want to be quicker (+ card draws always a bonus to reach your uniques)
Submerge is cool, and sometimes I'll sub in a [[putrid presence]] to really take advantage of that. But don't be afraid to put your stuff underneath if it wipes your opponents artifacts and minions out
[[Waveshaper]] tap ability will be essential from turn 6/7+ to gain time to build up a stronger field, and so site destruction can be challenging against it, make good use of [[overflow]] to keep [[waveshaper]] open to utilise the control when needed. Keep an [[order of the sacred oak]] in hand just in case they start site destruction
Hitting death's door fast isn't super worrying, focus on protecting [[waveshaper]] while you build up the body of water

Tsunami Sea

@Buns