Fate/Extra Last Encore screening already to the public last week, but on January 27, an initial impressions that display the first and second episodes were held in Japan. At that event also Atsushi Abe (Hakuno) Sakura Tange (Nero) and Kana Ueda (Rin) talks about the challenges of pemeranan this anime character.
For you guys who have been playing the game for surely you guys can see various changes to the story even though the concept is essentially the same. The seiyuu's also talk about this change and confessed at the time of the recordings they only were given relevant information at that session only. In short they also did not know anything about the progression of the story.
Because this change also voiced by adjusting each acting them. Abe said that acting Hakuno here differs from the version of the Drama CD. Tange stressed that language use this anime more masculine Hakuno. Abe could not explain more details but he felt this mystery-filled Hakuno. From my own observation is most likely because Hakuno Last Encore has the personality of a "Very resentful of the month".
Tange explains the difference of Nero from the anime compared to the game. In later versions of the game drawn by Wada Arco, Nero looks more "tomboy" due to ekpsresi of mostly delivered by static image, while in the anime version is livelier Nero expression so Tange decided to use a more "sweet voice".
Keep in mind that Fate/Extra has been released 8 years ago. What kind of story is either hidden from the cast. Regarding the Last Encore are written from scratch as the anime by Sounds we could likely see a story that didn't get implemented in the game.