The phrase "super zombies" refers to undead creatures that are much stronger, faster, or smarter than regular zombies. They are extra dangerous and difficult to kill or escape from. Full definition
And then they need to add in super zombies because then they realize how limiting the walking dead really are. (massivelyop.com)
In this speedy, Left 4 Dead - ish FPS, players are tasked with conquering map after map and wave after wave of increasingly difficult super zombies (called Zeds, to make them different, apparently). (gamecritics.com)
When nighttime settles in, players are introduced to the Volatiles, a breed of super zombie that is highly aggressive, extremely powerful, and hell bent on chasing you across the entire city alongside any other nearby Volatiles it can call out for. (shortpause.com)