Adam Cook’s review published on Letterboxd :
Werner Herzog is upfront in his condemnation of capital punishment but surprisingly Into the Abyss is not merely a critique of the inhumane system, even if it does question its effectiveness as a tool of law enforcement and punishment. Instead it attempts to explore why people kill and the ramifications of those actions on all those involved. Herzog is thorough in investigating every story from those now on death row to the family and friends of both the victims and the perpetrators. Unsurprisingly, it is a difficult and sombre experience that illustrates the utter senselessness of the murders, broken homes and the devastation it has caused.
Given Herzog’s normally ‘hands-on’ documentary style it is surprising to see him keep a relative distance. Whilst he probes and questions the interviewees off-screen his patented philosophical voiceover and guiding hand is largely absent this time around. Given the emotive subject matter his relative objectivity is a blessing (although he is a documentarian who is always deeply connected to what he is examining) as it allows the audience to come to their own conclusions rather than being forcibly led by Herzog’s own beliefs. It is a very humane film in a world where humanity is absent, it never tries to legitimise or excuse what the killers did but it does show them as people.
Tough, thorough, uncompromising and necessary.