[7] Rotten Tomatoes reports that 97% of 32 surveyed critics gave the film a positive review; the average rating is 8/10 with the consensus stating, "Nina Forever tests the limit of the rom-com with a decidedly unorthodox triangle that's as diabolically original as it is daringly dark".

[10] Patrick Cooper of Bloody Disgusting rated it 3.5/5 stars and wrote, "The Blaine brothers do a superb job of balancing the absurdity of a corpse that's summoned every time they have sex and the tough themes like grief and the possible impossibility of closure.

"[11] Drew Tinnin of Dread Central rated it 4/5 stars and wrote, "Always slowly developing just enough to stay interesting, Nina Forever strikes a fairly unique balance in tone, never winking and becoming too ridiculous given the circumstances while also dealing with loss in a very genuine way.

"[13] Matt Donato of We Got This Covered 3.5/5 stars and wrote, "The Blaine brothers' first feature is twisted, bloody, cheeky fun, but engaging performances from Hardingham and O'Shaughnessy create a combative fireworks show that impresses the most.

"[15] Michael Rechtshaffen of the Los Angeles Times compared it to Dona Flor and Her Two Husbands and said it "emerges as a diabolically effective anti-date movie".