gohan2988453,007 Locked 23 Feb 2012 09 Sep 2012
All you have to do for this is collect all of the movies and interludes. Comes from just playing and beating all episodes in the game.
EvoHero points out -
For this and the achievement for getting all the CG and the illustrations, the achievements did not pop up until I entered the extras menu. If they didn't unlock for you at the conclusion of beating the last episode, give that a whirl.
Edit: It was pointed out by wiirule111 that playing on easy will not get you all of them. I played on Normal and got this achievement so hard is unnecessary unless going for other achievements as well.