Other mistake: Throughout the saga, blood has been shown as essential for vampire's healing factor, and Selene herself used her blood to heal people. Somehow, this time around neither her or her pal David think in any way of this basic fact, making a complicated trip to the vampire doctor necessary, who simply feeds the vampire kid some blood, the very first thing any vampire would do to regain strength.
Underworld: Awakening (2012)
1 other mistake - chronological order
Directed by: Bjorn Stein, Mans Marlind
Starring: Kate Beckinsale, Michael Ealy, Stephen Rea, India Eisley
Revealing mistake: Right at the end of the fight between Selene and the Uber-Lycan in the vampire coven, the Uber-Lycan throws Selene into some wooden panels, knocking her unconscious. As she travels through the air you can tell that she is suspended by wires; she travels far too slowly towards the wooden panels for someone who was just thrown. (00:48:35)
Trivia: Michael's brief appearance in the beginning of the film was actually cleverly repurposed stock footage of actor Scott Speedman from the previous films digitally added into the scene, mixed with footage of a body-double in his "hybrid" makeup. His brief appearance in the end (where we see him frozen) is a mannequin that was made up to resemble Speedman.