is a series of science fiction action-adventure video games by Nintendo. It chronicles the missions of space-faring bounty hunter Samus Aran, who protects the galaxy from the depredations of the Space Pirates and their attempts to harness the power of the eponymous Metroids. Metroid combines the platforming of Super Mario Bros. and the exploration aspect of The Legend of Zelda with a decidedly darker atmosphere and a greater emphasis on nonlinear gameplay.