Worldbuilding:
the landscape

2D Art:
drawings and paintings (eg. for the intro)

3D Art:
all the models, from a chair to a dragon

Textures:
the textures for the landscape incl. the models

Music:
music we need for the game design, since it's not "only" backgroundmusic

Dialogue:
dialogues :)

Game Mechanics:
everything that is running in the background, the scripts which make the skill system,  the magic system, all the features (like sailing or riding a horse) etc... work.

Story / Quest implementation:
adding the story and the quests to the world. It's the actual game design. This means brigning all the pieces together, breathing life into the world. A lot of scripting and worldbuilding is incuded here too.

Overall:
should be clear; it's the overall game development status