Nocturne is one of the best entries on the SMT franchise, it doesn't have that much demons like 4, but that's for the best.
It's world is intriguing, the characters have interesting ideals and there is no more law or neutral, this is a world of strength and Lucifer is very proud of that, plus is the best official unofficial version of DMC2.
The only problem this game has is the skill inheritance system. Is rng based and it sucks hard, you can easily lose 40 minutes in a fusion trying to get the right skills.
Also, don't fall for the Matador meme, this game isn't hard, learn to buff and debuff and you will make it.