Alan Mattli’s review published on Letterboxd:
Where The Report committed to the fundamentally uncinematic process of unmasking post-9/11 America's love affair with human rights violations, The Mauritanian seeks to put human faces on it – with predictably mixed results. Yes, Mohamedou Ould Slahi is the perfect subject through which to convey the horror of Guantánamo and the fundamental rottenness of the U.S.-led "War on Terror," and thanks to the cues Macdonald takes from Slahi's own memoir as well as a highly engaging turn from Tahar Rahim, the film ends up making quite the emotional impact. The flip side of this more Hollywood-tinged approach is that the whole affair is hopelessly overwritten, with virtually every scene not featuring Slahi feeling like it was written for a high school social studies presentation handout – so much hackneyed expository dialogue. Also, I'm not entirely sure what Benedict Cumberbatch was doing in this movie.