It's a Zoo; mulligan for your 1-drop minions, maybe hold on either Hand of Gul'dan and Expired Merchant if you feel confident in drawing the other half, and just go fast and hard before other decks know what's coming.

I often play Void Terror to "save" the attack buff from Man'ari Mosher, but it can be a good Boneweb Egg activator when Wicked Whispers just aren't getting drawn out.

The deck draws fast, thanks to Free Admission and Hand of Gul'dan, though the former has a slight failure rate as there are 2 sets of minions who aren't demons (being Boneweb Egg and Expired Merchant.)

If you feel that the deck just doesn't quite have the reach, Demonfire can easily be swapped out for Soulfire. While the latter does help us steamroll, Soulfire is better as the game goes on and more AoE comes online.