Well, ideally as an animated movie as per the original thought, but as I don't have a fortune handy and I can't draw worth a damn, if I actually made it myself, it'd be a storygame.
Which sort...? Depends. There are multiple ways this could go. Death Note and the films do share in supernatural elements and spirit beings. In contrast, Miyazaki's films have a hopeful outlook, and again, a more child-like whimsy to them, whereas Death Note was like watching a trainwreck--anyone who says they didn't see disaster coming and inescapably so from the very first episode ... either they're blind to foreshadowing or I call bullshit.