Mulligan :

keep Tracking, Blazing Battlemage and look for Stormhammer and Imprisoned Felmaw. Nothing else, Stormhammer and Imprisoned Felmaw are essential at start. You may keep Faerie Dragon vs mage, druid, hunter or any class that cannot contest it on turns 1 and 2.

Matchups :

Rogue, Mage, Hunter, Shaman : optimize your damage to hit fast and hard. Remember they cant heal, but they will make your life hard from turn 6/7. Shaman can heal, but not really before turn 8 if you put enough pressure.

Druid : put as much pressure as possible, sometimes even delay Stormhammer. Evasive Feywing and Imprisoned Felmaw are your friends. Maybe keep Phase Stalker ... not sure.

Priest : be careful with you minions that can be targeted especially with Shadow Madness,  Then use Stormhammer + HP as much as possible and hope they dont heal too much.

DH : vs tempo, keep Phase Stalker or Explosive Trap. Here you'll need to control a bit more, depending on your minions. Remember DH will have to stop to hit your minions with his face at some point.

Warrior : keep Phase Stalker or Explosive Trap vs Pirate version and hope they dont start too fast, count your life and the opponent cards, put pressure on all other versions.

Paladin : murloc, same as vs tempo DH. Libram ... complicated.

Tips :

Use the coin for Imprisoned Felmaw on turn 1 and Stormhammer on turn 2.

Play dragons after Stormhammer, even Faerie Dragon.

Scavenger's Ingenuity, Diving Gryphon and Phase Stalker are here to draw and help you to draw Stormhammer and dragons.

Trade only very dangerous minions, otherwise go face (Stormhammer + HP is 5 damage each turn).

Try to keep Corrosive Breath for lethal.

Do not delay too much the play of Rotnest Drake, even if there is no good target to kill. 6/5 turn 5 is very strong.