The visual effects were done by the Vancouver-based Image Engine. Before the broadcasting, "Atlantis" visual effects supervisor Mark Savela revealed that the episode would have the "biggest effects sequence viewers will ever have seen," which involved the epic space battle in the climax of the episode. Savela intended the visual effects to top the minute-long sequence of the Horizon missiles firing to the Asuran homeworld in the season three finale "First Strike". The sequence was reportedly so complicated that for the first time in the series, models were used to physically map out the action before creating the initial animatics. Gero later stated that the episode had a battle sequence that "we will not be able to top. It is "the" greatest special effects sequence that the show has ever done." The episode used an extent of special effects and had one of the highest budgets in the entire series, comparable with the series' pilot episode "Rising".