You first have to understand that this is an adaptation of a manga that's easily long enough to make 3-5 movies and which already has an anime adaptation that no doubt influenced the movie. So, yes, it's a bit of a live-action cartoon. Also, it's Japanese so don't expect Hollywood-level special effects but, even still, they did a pretty good job with the bears, Retarr, etc.
Most of the casting is great, costumes are on point, scenery is excellent. The scenes inside Abashiri prison look like they were probably shot on-location. It's a museum now, you can go there next time you're in Hokkaido (pick up a few bottles of Abashiri Prison Stout from the gift shop and thank me later).
I was worried that they'd try to condense the whole long story down to fit into movie length which would really ruin it. I'm very glad to see they haven't done that which means they're hoping to film a series of these. Hopefully they will but, if not, there's still the excellent anime series.