I love this concept. Zee spends a lot of time apologizing for it not being balanced, but balance isn't the chief concern of TTRPGs it's just a consideration and sacrificing a bit of balance on the altar of fun worldbuilding and intricate tactics is totally worth it as long as you don't go completely off the deep end.
I like the core concept, but I have to question how practical using any of these rules become at higher levels. Shadow, in particular, just seems really dodgy especially relative to Light, which is comparatively cut and dry at least through 5th level. Death sounds like fun, but also seems to practically invite the Murder Hobo style of play.
Like, its definitely an interesting idea. And I'd probably go in for a Let's Play or something. But as a practical consideration of a long-running game... idk, man. This looks like its going to be a total mess in practice.