I have completed this game twice, once on my ps4 long ago and now here on steam, my thoughts are more or less the same after so many playthroughs so i will give info on this if you are going for completion.

If you want to complete this game without being a pain in the ass, either do a playthrough where you already know the game and already know everything that will happen or you play the game through first blind and then pick up what you lost along the way.
Be warned: if you do decide to clean up after a first playthrough there will be ALOT of walking around places you already been with no dialogue and it will get tedious really fast and clearly not intended to be done that way, If you are Ok with looking up where is what than you will have a significant easier time with this method but still a ton of back tracking.

final advice: the odin ravens make a distinct chirp noise when you are near them, even if you are iffy on completion, kill every one you see, thank me later.

I have completed this game twice, once on my ps4 long ago and now here on steam, my thoughts are more or less the same after so many playthroughs so i will give info on this if you are going for completion. If you want to complete this game without being a pain in the ass, either do a playthrough where you already know the game and already know everything that will happen or you play the game through first blind and then pick up what you lost along the way. Be warned: if you do decide to clean up after a first playthrough there will be ALOT of walking around places you already been with no dialogue and it will get tedious really fast and clearly not intended to be done that way, If you are Ok with looking up where is what than you will have a significant easier time with this method but still a ton of back tracking. final advice: the odin ravens make a distinct chirp noise when you are near them, even if you are iffy on completion, kill every one you see, thank me later.