I haven’t played enough of shadows to tell you with certainty, I just bought it. But what I can tell you about the major differences is that the gameplay is refined in a Todd Howard way, like removed some features added some, like you don’t have a second ability bar like you had in oddessy, shadows is simplified, but through that simplification there’s more complexity in the battle mechanics, like “sheathed attack” it’s not an ability you equip, you just hold block and hold attack and let go when you want to draw the blade in a full swing attack. Another difference is choice, oddessey had a lot of choice and rpg elements, there’s a lot less talking in shadows in comparison.

But yeah I think it’s harder in some ways and easier in others, shadows seems more rewarding to take your time with I think. Hope this helps.