Continuity mistake: Peter walks into the bathroom holding a box of Chinese and a bottle of wine. He puts them down and hugs Sarah. She falls backwards into the bath and now he too is holding a glass of cloudy looking water. (00:08:25)
Continuity mistake: When Peter and the subway guy crash down from the wooden platform, Peter's glasses are broken. Later on we see him fix the electricity with his glasses, and now they are fine.
Continuity mistake: At the water filtration plant, there is a 2 second shot of Jeremy pretending to play guitar. During the shot, his ear-protectors are not around his neck. (00:43:10)
Continuity mistake: When Susan is sitting on the edge of the bath, her hands are empty. Peter walks in, she puts her arms around his neck and now she is clutching a glass of water. (00:08:10)
Plot hole: Susan theorises that the insects have evolved to resemble people because of predatory pressure. However, for this to be true people must have been killing them - apart from the handful of 'moles and junkies' (who were the prey, not the killers) this film shows the first contact between humans and the evolved 'Judas bug'.
Continuity mistake: At the beginning of the film, Susan puts down her insect killing box in a patch of light in the tunnel and another patch of light is visible a few meters behind her. Just before and, more, at the end of the scene the wide shots show that there is just one light patch and that the rest of the tunnel is dark. (00:05:40)
