Mega Man 2: Dr. Wily's Revenge is a platform action game released by Capcom for the NES on December 24, 1988, the second entry in the original Mega Man series. It retains the core gameplay of its predecessor: players control Mega Man to battle the evil Dr. Wily and his eight new Robot Masters—Metal Man, Air Man, Bubble Man, Quick Man, Crash Man, Flash Man, Heat Man, and Wood Man. Each boss has a unique weapon and themed stage; defeating them grants Mega Man their special weapons. New items like energy tanks let players refill health anytime, and a password system saves progress. Graphics and controls are improved over the first game, with a soundtrack by Takashi Tateishi and sound effects by Yoshihiro Sakaguchi. Selling over 1.5 million copies, it is the second best-selling Mega Man title and widely praised by critics as one of the best in the series.