It seems that other reviewers have done a good job explaining the lore, missions, comparison to dark souls, etc.
I rate this 5/5 because the combat system is the best of any game I’ve played to date. It’s really fantastic and has so much depth. I chose the katana and Odachi to use, I’m now 80hrs in and still learning/practicing things like Flux II, shadow strike, etc. Raising your skill level and unlocking more abilities makes you waaaaay more mobile and safer while attacking, all without the moves feeling cheap. As you progress, even one or two the most basic enemies can humble you instantly if you aren’t careful and diligent. Very very cool. Will play this for a long time to come.