More interesting and varied level design - it's not the easiest thing to spell out, but the first game lacked the kind of smart occlusion that makes Souls level design so masterful. I remember entering the second part of the first level in Nioh, and you could see from the shrine the route you needed to take to get back to open the short cut, so I just ran it, got it open and did the rest of the level from there - kind of on me, but not great level design. Nioh 2's levels are better structured for that kind of organic discovery bringing you out in unexpected places and employ a great deal more verticality. There's also more optional things built in - in the first level there's an optional mini-boss that will open an early short-cut if you can beat him - the second level has several hidden areas and paths with additional loot and return loops.
The revamped skill trees for each weapon are much easier to understand at a glance (granted, they were awful in Nioh) and you've got nearly double the weapons of Nioh's base game. Soul Cores, Yokai Shift, Yokai Skills, the Yokai skill tree and their interplay with your Guardian Spirit(s) add a far more meaningful dimension to your build than Nioh's Living Weapon (which was very set-it-and-forget-it for me).
Really good character creator that you can revisit as often as you like - it's a small thing, but being able to add fresh scares and tattoos to my character during the course of play was a nice role-play experience.
Benevolent Graves bring some much needed balance. It's a hard game and I love hard games, but sometimes, when you're hitting a wall or re-running an area to farm, it's nice to have a little support on-side.
On top of that, there's a huge selection of armour, way more varied enemies and encounters throughout and a new burst counter move which is excellent risk-reward design.
