Adam Wingard’s latest film is a too-slick wannabe grindhouse action-slasher lacking the engine necessary to power it. Photo: Richard Foreman/A24 Directed by Adam Wingard — the filmmaker behind the fun, synth scored action film The Guest and propulsive yet silly fare like Godzilla versus Kong — Onslaught is the kind of film that should get my pulse racing. After all, it’s about undead super soldiers who unleash bloody havoc on an isolated trailer park in the American desert, only to meet their match in a mother who actually has something to lose and is stricken with PTSD from her time...