It's a very good game, but I would say not a very good RPG, I think it's much closer to a hybrid of immersive sim and RPG.
Why I say this is simply because the game does not go full out with its RPG design. The major limiting factor is the fact that you play Henry, a character with an established history and personality. This can be very conflicting in RPG design, which I experienced when playing Henry one way, and the game because it has to conform to Henry's history and personality, completely breaks the roleplaying of a RPG - a RPG isn't simply stats and gear.
For example the game has mechanics for thieving, which is a lot of fun, but even very early in the game there's a quest where you are tasked to steal something (I can't remember what it is now exactly), and then Henry responds to the other person saying he's no thief... yet I was playing Henry and intentionally stealing prior to this because I found it fun, I wanted to roleplay as a Thief, and it was a good way to make money. In a good RPG this disconnection does not occur, in fact it would take advantage of how you are roleplaying, giving you dialogue and choices of thieving/being bad, e.g in a game like Fallout: New Vegas. Not to say this is a constant problem in KC:D, but it occurs frequently to be noticeable and bother me.
Again something you experience earlier is with how you pillage corpses for items/money (of your own volition), and then there is a quest where you have to go pillage a corpse, and Henry responds disgustingly that he would never do such a thing... this is a major problem I have with games that try to be RPGs but use established characters with a personality, because quests and dialogue have to conform to that personality, you can't do it the way you want like in a RPG like F:NV or whatever. In F:NV I get to decide the character, the game uses mechanics to allow me to play that way and make dialogue choices appropriately, and it does ability score checks to ensure this.
Nonetheless, from an immersive sim point of view I think it's fantastic with all of its game mechanics and world design, and it blends well with what RPG mechanics do exist, but to me I don't think I can say it's a good RPG because it misses the part of roleplaying a character you want. It gives you just enough player agency between an immersive sim and a RPG, but not enough to be a full on RPG (again, I can't actually *be* a thief even if the mechanics exist, because Henry is written not to be a thief, so his personality, things he says completely break with that). Props to how well the landscape is captured and the scale, of course it's based on the historical region, and a lot of that part of Europe that extends in Germany, Czech Republic, Hungary, Poland, etc looks identical with the nuanced variations in hills and plains, how the landscape looks is probably the most realistic I have ever seen in a game and it feels so relatable because it's exactly what you see when you travel the country side.
The game does a bad job of introducing its combat and 90% of it can't be experienced early in the game, I didn't like it at first at all, but it becomes really nuanced with so much depth the more you play.
