i really like the Style, UI and animations. But! I think the roll system is still the weak part here like DevGio mentioned.
The invincible frames are either too short or buggy as i got hit too often while rolling. The side sweep attack was nearly impossible to dodge somehow (normally rolling into the swinging sword in DS or ER helps with the short time I-frame but it was here often a mistake). And rolling away was even more strange getting always hit. This part is really important and makes the players too quickly frustrated.
Best Example is Bleak Faith: Forsaken where players lament about the same issue, while on the other hand the promising V.A.Proxy Demo showed a counter system with a very wide timing friendly part. Its better creating the difficulty of the game by not reducing the evasion possibilities. Gamers who don't understand the intention or programming process may think its just Jank, influencing others then. (Even more professional gamers see it that way sadly)
For difficulty, the Boss should either turn slower to the Player to give more time for an attack, gets staggert sometimes or does sometimes a stupid recharging segment in his pattern.
Overall i enjoyed this game and hope you will develope this idea further.