Wonder Boy ROM Download for Sega Master System (Sega Master) on Emulator Games. Play Wonder Boy game that is available in the United States of America (USA) version only on this website. Wonder Boy is a Sega Master System emulator game that you can download to your computer or play online within your browser. You can also download free ROMs such as Wonder Boy In Monster Land, Wonder Boy III - The Dragon's Trap and Wonder Boy In Monster World as shown below. Wonder Boy works on all your devices in high quality.