I wasn't expecting much when I started watching this, but that quickly changed thanks to the brilliantly lit scenes and grainy, pensive mood of filming. The acting, as well as the violence was well above average in quality and brutality respectively, and the story was refreshingly original.
I believe three things could have elevated this movie to brilliance: 1. A more sweeping, bold orchestral soundtrack. 2. More sweeping, cinematic shots to give us short escapes from what, at times, became a claustrophobic atmosphere. 3. Authentic native language with subtitles, as was given the Vikings. I realize the choice not to do so (point #3) was probably based on perceived audience appeal, or perhaps even on the psychological identification with the "good guys", but it would still have added an element of greatness.
Overall I give Pathfinder 8 out of 10 stars for originality, brooding (amazingly refreshing) filming, and an authentic truthfulness in telling what was a simple but bloody tale of revenge. I also appreciated the fact that the film took itself seriously, and did not toss in a heap of "humorous" moments that so many current action movies seem to rely on. This movie was relentless in its pursuit of telling a dark and bloody tale and, for the most part, succeeded in providing an excellent couple hours of escape.