In its storytelling particulars, Shiva Baby is tightly contained and rendered with exquisite efficiency. Most of the film takes place among the grieving noshers at a shiva, where college student Danielle (Rachel Sennott) twists and cringes as a fleet of her questionable decisions converge at once. The bustle of the packed gathering only accentuates the tension Danielle feels as she futilely games out some sort of escape — either physical or emotional, or maybe even existential — from the eddy of angst she finds herself dizzied by. As written and directed by Emma Seligman, who adapted her own short film for this debut feature, the film is a crackling comedy that proceeds like an extended thriller set piece, intended to prompt beading sweat on the brows of any viewer with even an smidgen of empathy. Working with editor Hanna A. Park like a skilled, seasoned dance team, Seligman demonstrates a command over the mechanics of film narrative that recalls the raw, rambunctious instincts of Steven Spielberg back when he cracked free of his cocoon with The Sugarland Express. Within this formidable framework, Sennott delivers a remarkable performance that meets the demand. The steadily amplifying turmoil of her character is always evident, as is the effort of goddesslike strength she mounts to keep up just enough of a guise to get through the misfortunes of her afternoon. Shiva Baby is a marvel, all the way through to its beautifully crafted ending of deadpan understatement that nonetheless maintains the film’s ceaseless din.