[11] Preston Barta of the Denton Record-Chronicle gave the film a positive review and wrote, "It's a lovable cinematic Frankenstein of '80s movies and television that's peppered with exciting camera tricks and dazzling production design".

[12] Rich Cross of Starburst gave the film a negative review: "The result is a surreal tale that aims to blend the corpse comedy of Weekend at Bernie's with the macabre motifs of a Tim Burton fantasy, but which ends up strangely devoid of life.

"[13] Chad Collins of Dread Central awarded the film two stars out of five and wrote, "The Loneliest Boy in the World is a pastel zombie throwback of sitcom terror whose innate wholesomeness can't compensate for the sense that these undead themes have walked a hundred times before.

"[16] Simon Abrams of TheWrap gave the film a negative review and wrote, "The gags in The Loneliest Boy in the World also tend to be so broad and lazy that it's hard to imagine how this movie's retro-bait sensibility will appeal to anyone other than the targets of this poisoned-apple crowdpleaser's toothless criticism.

"[17] Meagan Navarro of Bloody Disgusting awarded the film three skulls out of five and wrote, "It's a simple yet charming story that uses the sitcom format to satirize the nuclear family while offering the protagonist a chance for growth through escapism.