Ys 2 was the second game Mantra brought to Korea after Princess Maker. But instead of just porting one of the many available home computer or console versions, Mantra assembled a whole development team — at least partly recruited from the stores' customers — to recreate the entire game.
Other than completely redrawn graphics and a remixed soundtrack (with even one entirely new tune) by the then relatively new team TeMP, who delivered their first published work with this game, Mantra also expanded many of the field maps and added some new events, including a new dungeon called Dan'gun's Tower. They also left in a lot of bugs. According to the former sprite artist of the game, the team hastily finished the game after several delays for fear of the company boss' wrath (who also happened to be the father of the development team lead)1.
Advertisements for the game announced also a music pack, a speech pack and a CD-ROM version, none of which was ever released. The same goes for the promised remake of Ys 4.
Read more about Ys 2 in the Ys article.