RPG games are adventure games where you play as one (or more) character (s). Your hero will have to explore the world, meet new people and do some quests.
RPGs have the longest lifetime of all games. Sometimes, they have, in addition to the main story, side quests and hidden objects.
RPG games differes from pure quest/exploration games because it contains a hero character that evolves throughout the game.
Embark on an adventure and try a quality RPG game like Castaway or Castaway 2.