What struck me the most was the verisimilitude of the characters and settings. The characters lived in modest homes in mixed neighborhoods. The police station looked like a mediocre office with ugly cubicle walls, not a high-tech laboratory. The police captain was a well-meaning manager with limited case insight, not a super-detective with a perfect moral compass. The primary characters are all complicated, not stereotypes. Everyone had character flaws but they mostly weren't defined by them. Morality was uncertain most of the time.
The acting and characterization were both excellent, and the direction quite good. The writing was fairly solid, although I didn't find the overall plot arc to be that surprising or rewarding. The plot was just there to give motivation to the acting.
There are a couple of scenes with some violence if that troubles you, but that's a fairly small part of the film as a whole, which is more of a drama than it is suspense or action.
Worth the time.