Variety has a positive review. The Telegraph gives it 4 out of 5 stars and says it's "pretty much everything you could possibly want a zombie film to be." The New York Times has a positive review.
Empire Online gives it 4 out of 5 stars and says it's "One of the best horrors of the year: innovative, effective...". The Guardian gives it 4 out of 5 stars and says, "This rip-roaring, record-breaking South Korean zombies-on-a-train romp barrels along like a runaway locomotive," also, "Yeon Sang-ho’s breathless cinematic bullet train boasts frantic physical action, sharp social satire and ripe sentimental melodrama designed to reach into your ribcage and rip out your bleeding heart."
Roger Ebert's site gives it 3 out of 4 stars and opens their positive review by calling it "the most purely entertaining zombie film in some time, finding echoes of George Romero’s and Danny Boyle’s work, but delivering something unique for an era in which kindness to others seems more essential than ever." Rotten Tomatoes has a critics rating of 95%.