▁attacks , ▁the ▁number ▁located ▁on ▁the ▁matrix ▁represents ▁a ▁number ▁the ▁acting ▁player ▁must ▁roll . ▁ ▁For ▁other ▁actions ▁( such ▁as ▁determ ining ▁the ▁result ▁of ▁radiation ▁expos ure ), ▁the ▁matrix ▁result ▁indicates ▁a ▁non - neg oti able ▁result . ▁ ▁G amma ▁World s ▁first ▁two ▁ed itions ▁had ▁a ▁variety ▁of ▁special ized ▁matrices ▁for ▁different ▁situations ▁( ag ain , ▁closely ▁res emb ling ▁D & D ). ▁ ▁The ▁third ▁edition ▁rules ▁replace ▁special ized ▁matrices ▁with ▁the ▁Action ▁Control ▁Table ▁( ACT ), ▁a ▁single , ▁color - coded ▁chart ▁that ▁allowed ▁players ▁to ▁determine ▁whether ▁a ▁character ▁action ▁succeeded , ▁and ▁the ▁degree ▁of ▁success , ▁with ▁a ▁single ▁roll . ▁ ▁( The ▁A CT ▁concept ▁is ▁drawn ▁from ▁the ▁Marvel ▁Super ▁Hero es ▁game ▁published ▁by ▁T SR ▁shortly ▁before ▁development ▁of ▁G amma ▁World ' s ▁third ▁edition .) ▁ ▁The ▁A CT ▁requires ▁the ▁ref eree ▁to ▁cross - reference ▁the ▁difficulty ▁of ▁a ▁character ▁action ▁with ▁the ▁ability ▁score ▁used ▁to ▁complete ▁that ▁action , ▁determ ining ▁which ▁column ▁of ▁the ▁A CT ▁is ▁used ▁for ▁that ▁action . ▁ ▁The ▁character ' s ▁player ▁then ▁roll s ▁percent ile ▁dice ; ▁the ▁result ▁is ▁compared ▁to ▁appropriate ▁column , ▁determ ining ▁a ▁degree ▁of ▁success ▁or ▁failure ▁and ▁elimin ating ▁the ▁need ▁for ▁second ▁result ▁roll ▁( e . g . ▁the ▁damage ▁roll ▁that ▁many ▁games ▁require ▁after ▁a ▁successful ▁combat ▁action ). ▁ ▁The