▁over night ▁in ▁the ▁UK ▁and ▁received ▁a ▁ 1 9 . 4 %. ▁It ▁received ▁an ▁App reci ation ▁Index ▁score ▁of ▁ 8 2 . ▁Over all ▁the ▁episode ▁had ▁ 5 . 7 6 ▁million ▁view ers . ▁ ▁Crit ical ▁reception ▁ ▁" The ▁Z ygon ▁In vas ion " ▁received ▁positive ▁reviews . ▁Based ▁on ▁ 1 8 ▁critic ▁reviews , ▁the ▁episode ▁holds ▁a ▁score ▁of ▁ 9 4 % ▁on ▁Rotten ▁Tomatoes , ▁with ▁an ▁average ▁score ▁of ▁ 7 . 7 4 / 1 0 . ▁The ▁site ' s ▁cons ensus ▁reads ▁" With ▁" The ▁Z ygon ▁In vas ion ," ▁Doctor ▁Who ▁del ivers ▁a ▁thr illing ▁episode ▁that ▁pays ▁special ▁attention ▁to ▁character ▁development ▁and ▁the ▁consequences ▁of ▁time ▁travel ". ▁As pect s ▁of ▁the ▁episode ▁particularly ▁pra ised ▁by ▁critics ▁included ▁the ▁character isation ▁of ▁Os good , ▁the ▁cl iff h anger ▁ending ▁and ▁the ▁political ▁them es ▁running ▁through ▁the ▁episode . ▁ ▁Tim ▁Martin ▁of ▁The ▁Daily ▁Te legraph ▁awarded ▁the ▁episode ▁four ▁stars ▁out ▁of ▁five , ▁particularly ▁pra ising ▁Os good ' s ▁character isation ▁as ▁" E arn est , ▁resource ful ▁and ▁an ▁un ab ashed ▁super fan ". ▁Ross ▁R ued iger ▁of ▁New ▁York ▁Magazine ▁highly ▁acc laimed ▁the ▁episode , ▁award ing ▁it ▁five ▁stars ▁out ▁of ▁five . ▁He ▁opened ▁his ▁review ▁by ▁saying ▁that ▁the ▁episode ▁" arg u ably ▁became ▁the ▁most ▁important ▁Doctor ▁Who ▁episode