Connor Denney’s review published on Letterboxd :
The Mule is a relaxed, personal film that feels a lot like Clint Eastwood simply spending some time with us in a natural, perhaps self-inspired role. It's a meditation on aging, as Earl's old age is constantly brought up as some perceived impediment (with Earl both disputing and acknowledging certain drawn conclusions). The film opens up opportunities to show how tenderness and unassuming wiliness can take you far; though Earl has made his share of mistakes, not all of which are reparable, his good spirit and industriousness give him the best shot he's got. In a way, the film might be summarized as "Do Your Best," a hilarious concept for a film about a drug mule. The film's quality is probably best perceived in individual character interactions: the first meeting between Earl and Colin, for example, is a bit of a masterclass in expectation subversion (the two opposing forces bond over some paternal advice) and gradual character development (we can almost see Colin's attitude change before our eyes).