Okay. Let's start with the obvious: It is addicting. It is satisfying and it is cozy. Think fruit ninja but make it... rats lol.
Love the medieval fantasy concept a lot. It just has that dark fantasy vibe that makes it so appealing and nostalgic. Paired with that banger of a soundtrack (Spotify release WHEN????) and the map and character design overall, I am certain, it will have many fans in the future :) You have one already hehe.
I like that little story in the beginning. In my opinion, it is essential to understanding the game mechanic, so I would not recommend to skip it, as another commentator suggested. Otherwise one could think, that the player is the silly blonde guy - but luckily we are the cool, mysterious, dark, silent, brooding, (probably hot) and mighty guy. I am very curious about the further story. So far it is very promising and catchy.
Another thing I really appreciated is that the character is not the most powerful being from the start. We know, he has potential, yes. But we actively build up to that. It is poetic and realistic in a way.
I would also like to point out the skill tree. You really see how much thought went into it. I think the depth is very impressive and I like how you can modify the difficulty of the game to your own taste.
This being your first game is almost unbeliveable to me. I am really excited for the game release and all the future ones!
_______
Edit: Typo