I think this film is deeply misunderstood, much like the viking age, itself. It's not Lord of the Rings. It's a portrait of the past, given to you without context. And that's part of its brilliance. The world was a primitive place 1200 years ago. That wouldn't be as apparent or have the same effect if it presented in a way that made sense to our modern ways of thinking. Don't come to this film expecting an action packed marvel epic. This isn't an adrenaline rush. This is like a western version of a Kurosawa film, where violence is meant to be poetic and not eye candy. If you are familiar with the Sagas, you will understand that their purpose is poetic and not action packed entertainment.
Don't come to this film expecting Return of the King. Expect Rashomon, instead