Adaptational Jerkass: Anakin Skywalker is made even more cold and heartless than he was in the movie.
For example, rather than immediately slashing off Windu's arm, Anakin blocks his attempted attack on Palpatine, starting a pitched duel between the two.
Adaptation Expansion: The game expands considerably on the action set pieces to the point of making completely original content.
Vader himself is also capable of throwing out Force lighting, which he was pointedly not able to do in canon due to his cybernetic limbs.
As soon as he turns to the Dark Side, Anakin is capable of casting Force lightning, something he never learned to do as Darth Vader.