Introduction of Rex's Electro-Charger and John's Silent Arrow weapon systems.
This is the first time Rex and John wear their Centurion exoframe suits.
The origins of Doc Terror and Hacker as well as the Centurion team are shown in flashback.
Gog and Magog could be a reference to the 3-D movie Gog> in which they were service robots at a lab sent on sabotage by a remotely controlled super computer, NOVAC. If not directly referring to the movie, they are, at least, taken from the name of the twin cities mentioned in the Bible.