@Alrik, I don't think that experience points and upleveling are strictly necessary for an RPG. They help in that you can develop and attach yourself to your character. But if a story was written well enough, your characters decisions alone could make it an RPG, and simultaniously could attach you to your character.
an excellent point because things like myst and a weird game i played recently similar to myst did not involve levelling up and i would class those as rpgs as the story is not linear and your actions effect gameplay and the ending.
