I bought a similar system when I worked in China. The key selling point was indeed that it came with a bunch of pirated software - one cartridge was advertised as containing 50,000 games. But what was really interesting was that most of the games were pirated games edited with a sprite editor to insert other copyrighted content. Thus, the "Pokémon" game was really the 8-bit NES version of Donkey Kong, with a crudely drawn Pikachu in place of Mario. Unfortunately, some 10% of the 50,000 games were all versions of Donkey Kong with a different character edited in for Mario - thus Sonic quickly lost its appeal, as well.