Interesting one mechanically to say the least. I think controlling the two characters at the same time feels quite intuitive and adds a whole new layer of strategy to the game. It also helps that the two of them play quite differently. Sometimes Jonathan carries you hard with his strong physical attacks and bulk while other times you can utterly trivialise some enemies with Charlotte's spells. So the overall gameplay is pretty good.
However, I didn't enjoy the map being split into different sections. Making them separate just makes navigating through areas you wanna get to way slower because you gotta keep going through a billion portals.Also, the sidequest system doesn't work well, the rewards were either non-existent or underwhelming, making me question the entire point of this mechanic. The entire idea of sidequests in castlevania doesn't feel appealing anyway to begin with, I just wanna traverse the entire map and get strong weapons not collect cards.