Occasionally this paralysis will be accompanied by physical experiences or hallucinations that have the potential to terrify the individual.

[5] The Nightmare premiered at the Sundance Film Festival on January 26, 2015, before making its way to South by Southwest on March 13.

[6][7] On Metacritic, the film has a 69 out of 100 rating based on 16 critics, indicating "generally favorable reviews".

[9] The film received praise from media outlets such as Indiewire, Screen Daily, and Variety,[10][11] and Variety wrote that "Mixing talking heads, surreal bedtime re-creations and shamelessly assaultive scare tactics, Ascher's playful, visually inventive sophomore feature isn’t at the same level as Room 237 but that "it shares with its predecessor a warped affection for eccentric storytellers and a desire to give vivid cinematic form to their darkest imaginings, if that is indeed what they are.

[13] IGN was more negative, awarding the film a score of 3.5 out of 10 and saying "Like a person floating on the edge of sleep who never quite succumbs, The Nightmare grazes its subject but never truly dives in.