Character mistake: When John and Cassie are in the school library and look up about the disease, the book caption reads: "arm amuptation." The word amputation is misspelled.
Revealing mistake: John has to cut off his hand so the virus won't spread. Afterward, Cassie uses duct tape and wraps his stump up and you can see he is making a fist under the tape. (01:08:10)
Revealing mistake: When the girl is giving the guy a blow job in the school restroom, he finishes in her mouth. She goes to the sink and spits it out. You can obviously tell she had a mouthful of water going by the color and quantity. (00:20:45)
