This game is great if you like an overwhelming challenge, and if you like to play one level over and over again like 30 times. Just to learn the combat tactics of one boss, you need to fight and die like 20 times before you can beat him. I mean, is that fun?!
This is a Role-playing game with great action elements - and it MUST be well paced with smooth campaign progression for this game to be great. Not like this tedious campaign where you feel yourself as a weakling where even a chicken can deal you a significant damage, I won't even comment about the bosses who damage 90% of your HP with one hit and where you have to die like 30 times before you can progress. Moreover, you have veeery limited healing things.
Question: What is the point of playing a role-playing games? Answer: To have fun, enjoy the story, enjoy the action, enjoy the new experience, exploration, fighting new bosses and discovering new elements, upgrading yourself (in the game), and so on. NOT tiring yourself with sweat and anger!
This game will tire you a lot, and yes, you will be one angry nervous person while playing this game trying to progress through your campaign further. Can be a real reason for breaking the keyboards, joysticks, mouse, etc. So think, why are you playing this?
For the developers - I really started liking this game at the beginning especially the juicy combat, unless I started progressing further through the campaign. PLEASE STOP COPYING FROM DARK SOULS - Dark Souls is not a proper reference for great Role-Playing games. Let me guide you to The Witcher series, or Devil May Cry series, or AC Oddesey series, or TES series - where you meet a great challenge with great experience! The only element missing in Sekiro: SDT - you CAN'T adjust the difficulty! Which means that this game targets mostly the some freaks who like tedious challenge! The ridiculous damage taken could have been adjusted, or you could have added an HP regeneration element, or make better a healing system, or just be more creative. Just by adding one single element which is a difficulty level adjustment (like most of the adequate games do) - this game would be a great game!!