Uriaș (Lycan ambush)

Chapter: 2 · The Village (1st visit) · Lycan Ambush · Luiza's House
Where: East Old Town, the open area between the farmer's house, the stable and the water mill, with houses, rooftops and ladders.

Weak point

The head (×2.6 from guns; the rest of the body ×2.0). Explosives do ×2.0 anywhere.

On a first run this is not a fight: it is the Lycan ambush, and you have to survive it. Lycans keep coming until an automatic cutscene; halfway through, Uriaș, the hammer giant, shows up. He hits far harder than the Lycans and chases you swinging his war-hammer.

Killing him is optional and meant for New Game+ with strong weapons or infinite ammo. Leaving him alive costs you nothing: he comes back as a boss in the Stronghold (chapter 10) either way.

Reward

35,000 Lei if you kill Uriaș (one source adds a Crystal Skull, unconfirmed) and the Timber challenge (20,000 CP). Surviving gives the story challenge Not Lycan This...; killing 30 Lycans during the ambush gives Unstoppable (20,000 CP).

The data read from game memory has no separate figure for this Uriaș (the Stronghold one has 25,000 HP). One source says the ambush lasts about 4 min 30 s; another says it ends when you run down the channel after Uriaș appears.

Village of Shadows: hole up in the house whose basement is only reachable by a ladder (a single way in), use Explosive Rounds or Flashbangs if you get surrounded and drop Mines as you run. The ambush ends when a Lycan grabs you from behind.
Timber: PowerPyx suggests trying it on New Game+ on Casual, with infinite ammo.

Step by step

Before you leave, take the M1897 from the table in the middle of the farmer's house. At Standard's starting rank, one un-upgraded shell to the head (840 damage) kills a 700 HP Lycan.
Fight from the buildings: use them as chokepoints and climb onto the roofs by the ladders if you get surrounded. Shoot the flour sacks (the dust cloud hides you) and the red barrels when several Lycans bunch up.
Shoot each Lycan in the head before it strikes: it flinches, then lunges to grab you. Hold L at that moment and Ethan kicks it away.
If you only want to survive: wait until Uriaș appears, stop fighting and run down the path with the water channel between the buildings. That triggers the final cutscene: Ethan is grabbed from behind or hit by an arrow, and every Lycan withdraws.
If you are going for Timber (New Game+): hole up in the M1897 house, thin out the Lycans and, when Uriaș arrives, unload your strongest gun into his head (Game8 recommends the M1851 Wolfsbane and the GM 79).
Before you follow the old woman through the gate by the red barrel, pick up everything the Lycans dropped.