Christopher Landon's Happy Death Day not only transmutes the time-looping premise of Groundhog Day into a high-concept slasher comedy, it borrows the basic thematic structure of that film as well. Like Phil, the surly weatherman played by Bill Murray in Harold Ramis's film, bitchy sorority girl Tree (Jessica Rothe) finds herself reliving the same day over and over again, waking up every morning in the same bed to the same irritating song. The twist: Each day, Tree is murdered by a knife-wielding killer wearing a baby mask. Is it someone she knows or some random maniac? Only by solving the mystery and defeating her assassin can she break the cycle. And, as in Groundhog Day, the whole process teaches her to be a more caring, more compassionate person. It's self-improvement through endless repetition.
Scott Lobdell's script is derivative, and openly so: In the film's penultimate scene, Tree's love interest, Carter (Israel Broussard), expresses indignation that she's never seen Groundhog Day. But the clever tweaking of the slasher formula injects some life into the moribund genre. Happy Death Day twists the inherent repetitiveness of slashers to its advantage by exaggerating it to an impossible degree. If in the archetypal slasher film, a mysterious intruder kills a bunch of largely indistinguishable model-hot young co-eds over the course of approximately 90 minutes, here the masked predator literally keeps killing the same young woman over and over again. Working in a slyly self-aware style that benefits greatly from the way Rothe magnetically balances caustic spitefulness and wounded vulnerability, Landon uses these kills less as opportunities for gore—of which there's practically none—than as playful little set pieces resembling those in Doug Liman's similarly themed Edge of Tomorrow, in which each reset serves as a smash-cut punchline.
The fact that Tree's life isn't bounded by the usual laws of time and physics prevents Happy Death Day from generating much suspense—after all, each death is simply a rebirth—but the impossibility of the premise liberates Landon's film from mundane concerns about plausibility that sometimes bog down these sorts of productions. The filmmakers can pile on the killings without having to concern themselves with the attendant consequences, like police officers, the press, and worried family and friends. Unlike Rudolph Maté's 1949 noir D.O.A., which turned the theme of a man investigating his own murder into a kind of existentialist detective story, Landon and Longdell never explore their premise's built-in psychological and philosophical potential, content instead to utilize its relative novelty as a narrative stratagem to provide some bloodlessly entertaining thrills. There may be a lot of killing in Happy Death Day, but in the end, (almost) no one gets hurt.