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.
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)