Dr. Hello is an unlicensed Dr. Mario clone developed for the MSX and ported to the Sega Master System. It was developed in South Korea by a company known as "Sis Co." in 1991, without the backing from either Sega or Nintendo. The game uses a completely different set of graphics and music to Dr. Mario, but the gameplay is exactly the same. Despite being released on a Master System cartridge, the Master System version runs in SG-1000 mode, and hence appears to have weaker graphics than most other Master System games. This is likely because the MSX and SG-1000 share similar specifications, and porting from one system to another was not too difficult.