Contra - The Alien Wars ROM Download for Gameboy (GB) on Emulator Games. Play Contra - The Alien Wars game that is available in the United States of America (USA) version only on this website. Contra - The Alien Wars is a Gameboy emulator game that you can download to your computer or play online within your browser. You can also download free ROMs such as Contra, Alien 3 and Star Wars as shown below. Contra - The Alien Wars works on all your devices in high quality.