Story-related, cannot miss.

Towards the end of chapter 2, you’ll have to infiltrate the draugar infested village, Freyslaug. Once you get through the Rune door midway through the village, and sneak past the draugar under the cover of night, Senua will go against her better judgement and sneak into the village to save a stranger from a draugar ritual.

After a lengthy battle scene, Senua will have saved Fargrimr and ‘The Man in the Middle’ achievement will be all yours.