The atmosphere created by the sets, props, costumes and cinematography is very realistic. There were no overtly noticeable anachronisms.
A good example was the corpse, which was very detailed and realistic. There was no sign of life when the actor was playing the corpse. Initially the corpse was soft and malleable, as seen when the examine the cavity in the chest (Decomposition was slowed down by the cold winter outdoors). A few hours after the corpse was left indoors, rigor mortis had set in and the detective has to snap and pry the message from his dead hands.
The tone at which the characters speak is dynamic. When a character has been silent for some time and begins to speak, they start off with a shaky voice (as their vocal cords are ramping up). Their voices sound strained when they have been talking or shouting for extended periods of time, even when they have done so in the background or off camera.
Although this is a murder mystery of sorts, there are barely any clues laid about regarding the true nature of events. You are brought along for the ride through the winding narrative. There are some cliches of old "buddy cop" movies, but they are veiled quite well by the world built around the characters.
The beginning of the film is strong, but it becomes muddled somewhere in the middle. The scenes are most dark and gloomy (due to the winter), only lit by the faint candlelight at night, but it carried by the charged interaction of the characters. These interactions become lukewarm overtime, up until the detective has the epiphany, whereby it begins to ramp up again.
The ending is not the most ingenious for a murder-mystery, but the emotional exchanges tie the whole movie together.