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This video features the first boss fight of Hellblade: Senua's Sacrifice against Surt, the Fire Giant or the God of Fire, along with both the intro and the outro cutscene for said battle.
Notice that this video was recorded on the PC version of the game and while playing the game with the combat difficulty set to Normal.
Surt is the first boss of Hellblade and all in all not much of a difficult fight. While Surt's attacks cannot be blocked they are slow and telegraphed enough to give you ample time to dodge them (even when the boss will start chaining them into combos).
Even the last leg of the battle isn't much of a hassle, as you can overcome Surt's new gimmick, a fiery aura that will damage you if you'll attack, by activating your focus and cut the boss to shreds with impunity