Many reviewers were impressed by the film's originality. Dennis Lim of "The Village Voice" said that it was "the freshest thing the genre has seen since "", while in "The New York Times", A. O. Scott wrote that Carruth had "the skill, the guile and the seriousness to turn a creaky philosophical gimmick into a dense and troubling moral puzzle". Scott also enjoyed the film's realistic depiction of scientists at work, saying that Carruth had an "impressive feel for the odd, quiet rhythms of small-scale research and development".