5.5/10
The Deer King is an unfortunate bundle of squandered potential on all fronts of its story. It would not be hyperbole to call it "Walmart Mononoke Hime"
There are WAY TOO MANY 'riding' scenes, where character are in chase/pursuit and barely anything happens, and they last too long. "Look, this guy is riding a deer! holy shit!" x5
The pacing falls apart at about the halfway mark after dragging its feet through a slow slog of unnecessary scenes as the writers clumsily try to curry your interest in the world. It just screams budget issues as the pacing ramps up while the writers scramble to tie up all the loose ends.
The protagonist's character development falls flat. He is established as a large, brooding, quiet warrior with a tragic past, which isn't too hard to get right, but somehow he fails to be memorable in any way as his personable is slowly revealed to be that of an archetypal anime dad.
Throughout the story there are several significant plot points with great potential for interesting conflicts, but they are all glossed over and pushed aside as the studio slowly ran out of money. There is tons of buildup as you are groomed into expecting some sort of moral, a question to be left with, or a message-- but you, as the viewer, are let down one minute at a time as nothing is elaborated on.
Visuals wise, yeah, they're decent, sometimes good in a few places, but overall it's nothing special. It almost feels like the director is doing everything in their power to make fight scenes as short and sparse as possible and then replacing them with riding scenes.
It pains me to say this since the setting and world building is unique (for modern anime), but for most people this movie is just not worth watching. It's a 2 hour nothing burger and there are loads of better things to do.