So far it seems rather obvious what the game plan is, get big hydras and attack, then use spells for extra damage, but there is an order to it.
Ideal opening hand setup:
So in an ideal world we have at least one cheap ramp, either Elvish Mystic, or Whisperer of the Wilds, 1 Primordial Hydra, a mountain, 2 forests, Hardened Scales and one of our creature -> damage spells (Fling, Mage Slayer or Soul's Fire)
The game plan is to smash out Primordial Hydra ASAP for as much as possible. As soon as he reaches above 10 +1/+1 counters (or half the enemies life total at a minimum of 10) we attack and use one of the burn cards to finish them off.
Turn 4 win
Opening hand: Forest x2, Mountain, Primordial Hydra, Elvish Mystic, Hardened Scales x2
Top deck: Hardened Scales, Fling
turn 1: forest + mystic
turn 2: forest + hardened scales x3
turn 3: mountain + primordial (pay 4 mana playing him as a 5/5 with scales)
turn 4: (primordial is a 13/13). attack with primordial and fling in second main.
Alternate turn 4 win, a little harder to set up
Opening hand: Forest x3, Elvish Mystic x4
Top deck: Fling,
Relentless Assault
or Soul's Fire, Primordial Hydra, Mountain
Turn 1: forest + mystic
Turn 2: forest + mystic x3
Turn 3: forest + primordial for 7 mana
Turn 4: mountain, attack with primordial for 10 dmg (if they have a blocker you can pump him if you want, but turn 4 guarantees the opponent won't have a really big blocker) then you can either use SF, Fling, or RA
Yet another turn 4 win
Opening hand: 2x Forest, 1x mountain, xenagos, Primordial, mysitc, Somberwald
Topdeck: fling
T1: Forest mystic
T2: Forest Somberwald
T3: mountain Primordial with 5 counters
T4: xenagos (using Somberwald for Mana) Primordial is a 10/10, xenagos gives +10, attack for 20 with trample, then fling through the rest.