The reviews are warm and closely aligned. Most critics say the series is built around David Mitchell and that the fit is exact: an anxious, puzzle-obsessed introvert who becomes a detective by accident, played squarely to type. The praise clusters on the script, which critics call sharp and funny rather than twee, and on the puzzle-framing of each case, which several say lifts the show above a standard procedural. The supporting cast is mentioned approvingly across the board, and Anna Maxwell Martin’s chemistry with Mitchell is singled out more than once.
Where reservations appear, they cluster on mildness. Several critics find it gentle and low-stakes, and The Times suggests it is sometimes too mild for Mitchell’s talents. Radio Times notes it grows more generic once it settles into a case-of-the-week rhythm, and The i Paper thinks Maxwell Martin is underused. The spread is narrow: nine positive, one mixed, none negative. The one qualified verdict, from Den of Geek, still calls it satisfying.