way ' s ▁version . ▁Space ▁Inv aders ▁also ▁adopted ▁the ▁multi - ch ip ▁bar rel ▁sh if ter ▁circuit ▁first ▁developed ▁by ▁Mid way ▁for ▁Gun ▁Fight , ▁which ▁had ▁been ▁a ▁key ▁part ▁of ▁that ▁game ' s ▁sm o other ▁animation . ▁This ▁circuit ▁allowed ▁the ▁ 8 0 8 0 ▁CPU ▁to ▁shift ▁pictures ▁in ▁the ▁graphics ▁frame buffer ▁faster ▁than ▁it ▁could ▁using ▁only ▁its ▁own ▁native ▁instructions . ▁ ▁Despite ▁the ▁spe cially ▁developed ▁hardware , ▁N ish ik ado ▁was ▁unable ▁to ▁program ▁the ▁game ▁as ▁he ▁wanted — the ▁Control ▁Program ▁board ▁was ▁not ▁powerful ▁enough ▁to ▁display ▁the ▁graphics ▁in ▁color ▁or ▁move ▁the ▁enemies ▁faster — and ▁he ▁ended ▁up ▁considering ▁the ▁development ▁of ▁the ▁game ' s ▁hardware ▁the ▁most ▁difficult ▁part ▁of ▁the ▁whole ▁process . ▁While ▁programming ▁the ▁game , ▁N ish ik ado ▁discovered ▁that ▁the ▁processor ▁was ▁able ▁to ▁render ▁each ▁frame ▁of ▁the ▁al ien ' s ▁animation ▁graphics ▁faster ▁when ▁there ▁were ▁fewer ▁al iens ▁on ▁the ▁screen . ▁Since ▁the ▁al ien ' s ▁positions ▁updated ▁after ▁each ▁frame , ▁this ▁caused ▁the ▁al iens ▁to ▁move ▁across ▁the ▁screen ▁at ▁an ▁increasing ▁speed ▁as ▁more ▁and ▁more ▁were ▁destroyed . ▁R ather ▁than ▁design ▁in ▁compens ation ▁for ▁the ▁speed ▁increase , ▁he ▁decided ▁to ▁keep ▁it ▁as ▁a ▁challeng ing ▁game play ▁mechanism . ▁ ▁T ait o ▁released ▁Space ▁Inv aders ▁in ▁July ▁ 1 9 7 8 ▁in ▁both ▁an