Most critics receive Southcliffe warmly, and the praise clusters around Sean Harris as the gunman, whose performance the reviews describe as convincing and sinister in roughly equal measure. The wider cast is credited with holding the four parts together, and the same qualities come up again and again: an unflinching handling of the aftermath of a mass shooting, a stark and rather beautiful picture of the town, and a sound design one critic finds unusually realistic. Nobody treats it as anything other than serious work.
The reservations are about endurance and structure. The Telegraph wonders whether viewers will put up with such unrelenting bleakness from the first hour onward. Variety finds the nonlinear structure imprecise, and The Hollywood Reporter goes furthest, calling it superior middlebrow television with stilted dialogue and characters that lack depth. The spread is moderate rather than wide: no review is negative, but three of the seven stop short of a recommendation.