Here's a quick run-down on why this book is a 5-star
The setting is deep, immersive, and very close to actual norse mythology. It's actually so close to the myth that you can read texts from the Prose Edda and other traditionnal works and weave them directly into the game. The author also chose to eschew the vanilla "let's be vikings in norseland with gods" angle and actually trigged Ragnarok. The result is a neverending winter that feels very close to a post-apocalyptic setting (light sources and food are scarce, people fight for ressources...).
The system is clever, tactical and satisfying. Using runes seems like a gimmick at first but many mechanics (powers are linked to certain runes you draw so you don't get access to all your abilities in one given turn, your runes are withdrawn from the bag as you take damage so your options wither with wounds...) are really refreshing and give something very different from the usual roll and compare.
Every character option is interesting, with loads of flavor and actual use in and our of combat.
The book is a pleasure to read and it's just gorgeous, with either full-color or line art every single page.
You'll need to either find generic Elder Futhark runes somewhere and paint them up (for the color cues), buy them directly from Pendelhaven or print them up on carton. Obviously, stone/wooden runes feel a lot more tactiale and heftier, and play much better during an actual game. That's increased cost for a gaming group, but it's very playable with only paper runes nonetheless.
The rules are a little on the heavy side. They're perfect if you're a D&D/Pathfinder/OSR-avid player, but don't go in there looking for an indie ruleset.
All in all, it's a superb addition to most roleplayers' shelf, be it digital or physical.