Swamp Thing (Proto) ROM Download for SEGA Genesis (Genesis) on Emulator Games. Play Swamp Thing (Proto) game that is available in the United States of America (USA) version only on this website. Swamp Thing (Proto) is a SEGA Genesis emulator game that you can download to your computer or play online within your browser. You can also download free ROMs such as Prince Of Persia 2 - The Shadow And The Flame (Europe) (Proto), Sonic Crackers (Proto) and Lufia & The Fortress Of Doom (Proto) as shown below. Swamp Thing (Proto) works on all your devices in high quality.