Great game! Was finally able to get a few people on the couch to play. Some things that might help:
Journal/bestiary - I was excited when I found my first pet, but did not know what they did or offered. A journal that keeps track of monsters you have come across as well as different items and what they contribute to you.
Scoreboard/leader board: you may consider a few options here, but you can possibly make the player with most points in the previous level get a crown or some on screen glow or something denoting the current leader. Likewise, if you fail and die, it would be a nice feature for a high points leader board (possibly of the image of what spirit you were). You can even nod to the games past with a 3 letter name leader board, similar to the good old favorites or arcades past.
Male some object throwable: it might be nice to allow the vikings to throw barrels or weapons that have fallen from foes. Damage from different items would make for interesting game play. The only drawback would be to have it mapped to a key that will not stop one from dodging in or jumping. (possibly the shield button).
All in all, phenomenal game, great artwork and I hope to make it further to see more of what you all created.