Not much. I just get the impression from it that instead of any sort of military prowess is shown not by actual victories, but by how many enemies you can kill with your bare handsnothing to do with Norse mythology at all, Norse mythology alike most mythologies is like your everyday day time soap opera, full of intrigues and strategic moves.
The barbaric routine you mentioned is the work of the christian church, they tried to undermine the believes and mythologies of other cultures the best way they could..........make it kind of evil and pagan.
The Vikings were just like any other army, the progress was shown in won battles not how many enemies slain, the latter was the work of "skaldene"( the scalds) to praise the "bad asses" of the battles to boost/promote the outstanding fighters because rank and social position.
of course the exaggeration of the deeds of prominent warriors went beyond the truth. The worse the deed the higher your rank and easier the access to Valhall was ensured ( you had to die of a wound to enter Valhall though .)