As Reference (Metacritic Scores):
Ninja Gaiden Black: 94
Bayonetta: 90
Bayonetta 2: 91
NiOh: 88
BloodBorne: 92
Challenging games have never stopped reviewers from giving out high scores in the past.
DMC games are challenging but usually give casual players enough options and means to get through the game and have a lot of fun. Its not like this is La Mulana or anything where you gotta work just to advance a tiny bit.