From Sega Retro
Zemina (재미나) was a South Korean video game developer established in 1981. Zemina were one of many companies which provided software exclusively to the South Korean market, beginning with the Daewoo Zemmix (an MSX computer) before progressing to the Sega Master System. The company faded away during the 1990s, presumably as copyright laws became more strict and Japanese competitors were allowed to enter the market.
South Korea lacked copyright laws for computer programs until 1987, so Zemina spent many years hacking overseas games for a South Korean audience. The legality of some of their later releases is also questioned too, as newer laws only protected the game's code, not intellectual property rights. It is unknown whether Zemina had permission to create games for Sega's Master System (which was distributed by Samsung), or whether they had permission from third-party developers (such as Konami) to bring their games to the system.
Many of Zemina's Master System games were ports of MSX games which were themselves pirates of commercial games. These typically run using the Master System's first graphics mode (which was used for backwards compatibility with SG-1000 games), meaning they are essentially SG-1000 games "in disguise". This is because MSX and SG-1000 hardware is very similar in design.