Plot hole: (Ep. 5) The weapon Stephen finds in a desert is a H&K G36. He states that it's not a military weapon and is mainly a mercenary weapon. The G36 is used by several police and special forces units in the world, including the British SAS, which could suggest another nation's or British government branch's involvement. Comment was probably made to deepen the intrigue of the season plot.
Continuity mistake: (Season 2 Episode 2) Near the end, as the worms have died and exploded trying to spawn, a shot shows Cutter, Claudia and Stephen ripping the spawning worms from their bodies. Stephen is shown with one in each hand and another hanging on the right of his chest. In the following shot he is seen ripping one off his right chin, which did not have any worm on it in the previous shot.