This takes Cairn and adds some extra stats and a strong Norse theming. Overall, though, the feeling is that it is streamlined. This Core Edition is meant for one player and one GM, but it is easy to play solo, especially with the form-fillable character sheet, which is the best I have ever seen. The feeling is definitely one of a single-player action RPG (Dark Souls is the clear inspiration).
That said, the advanced Wardensaga edition is only six quid more, and that does contain rules that make solo play easier. Definitely, for solo play, pick up some of the additional books.