Complete Monster: The scientist-magician Valruda mass produces "military dogs", by combining the DNA of people—rumored to kidnap orphans for this purpose—and dogs, condemning them to unquestioningly serve whoever makes a pact with them. Selling the dogs throughout the nation, they are generally used for war, as bodyguards or just slave labor, Valruda puts thousands through unending suffering. Throwing out Fultac after deeming him a failed experiment, Valruda is shown dumping him in a sewer littered with the drowned corpses of other dogs he deemed failures, seeing his creations as nothing more than his own artwork to do with as he pleases.
Nightmare Fuel / Nausea Fuel: This being made by Hiromu Arakawa, there are scenes in labs involving images of flesh, organs, mutilations and whatever other horrible stuff that there are on experimentation on humans.
Harsher in Hindsight: The idea of a police officer's issued weapon being used for crimes is especially harsh, considering that a bad guy in a country/territory with strict firearms control like Hong Kong, Japan and South Korea could attack/ambush officers doing their duties by themselves or steal from squad cars. In June 2019, Osaka Prefectural Police have been conducting risk assessments after officers manning kobans (alone for the most part) were attacked, sometimes killed, with their sidearms taken.
Iron Woobie: Murakami. He's vulnerable and haunted by his own guilt throughout, but he's incredibly tenacious.
Spiritual Adaptation: Of the detective stories of Belgian-French writer Georges Simenon, which director Kurosawa admired; though not a direct adaptation of any specific work of the author. Simenon ended up writing Maigret's Revolver in 1952, with a plot with similarities to Stray Dog (1949).
