Complex sentence: Sega was one of the primary competitors to Nintendo's video game consoles, and a few of Sega's early consoles outsold their competitors in specific markets, such as the Master System in Europe and the Sega Genesis in North America.
Split into simpler sentences: Sega was one of the primary competitors to Nintendo in the video game console industry. A few of Sega's early consoles outsold their competitors in specific markets, such as the Master System in Europe and the Sega Genesis in North America.