Steven Sheehan’s review published on Letterboxd:
The wider context of where this story takes place importantly reminds us of 1980's South Korea, a country run by a Government still heavily influenced by the military. Sporadically placed around the police investigation we see the paranoia and fear of a country undergoing nuclear drills, its citizens under full control. At the same time a serial killer roams the provinces undermining the authorities apparent grip on society.
You would expect the police force to reflect the accurate efficiency of the ruling power but what the South Korean people get for protection would struggle to make the cut with Maloney and co at Police Academy. It doesn't take long to realise how far out of this depth Detective Park is watching him pick out his suspects based on instinct rather than any sort of solid police work. Song Kang-Ho brings this arrogant country cop brilliantly to life constantly sneering and belittling everyone around him.
Their ineffectiveness in coping with with the scope of the investigation allows us to continually laugh at how unprepared they are. When Detective Seo arrives from Seoul the contrast between their gun-ho attitude and his professional, documented approach only makes matters worse. The police chief is no more competent in his job, only stepping in to stop the two men from tearing each other to bits.
Joon-ho Bong really shouldn't be able to shift between moods as he does so effortlessly, letting us laugh out loud one minute then mournfully watch a coroner detail the gruesome death of a young woman. The narrative goes from comedy, to suspense before ending in regretful, melancholic mode, rain covering the water in their eyes.
Memories of Murder creeps up on you before you realise how effective it has been. By the end you are pitched head first into this investigation with the two detectives, sharing every inch of frustration that the two men are facing. The film ends as it starts with Park talking with a child as he revisits the scene of the first murder. Once again he has just missed out on finding the killer and all he has left are memories of what could have been.