In 1st mission yes and with cheats yes
Yes on the first level
yea, but when you play as Darth Vader you can't.
Yes. Once you master alll levels exept the last 4, you will not be able to play him.
No, you play as Darth Vader's Secret Apprentice (Galen Marek). The only other person you play as is Darth Vader at the beginning and you can choose other skins to use (like Kota, PROXY, Organa, etc) by using Cheat Codes.
Darth Vader's "Secret" Apprentice. He's referred to as Starkiller. Play the game or read the book for more info. Don't wanna spoil it for ya!
You play as Vader during the game's intro level (or Prologue). You can't play as him after that. However LucasArts is going to release updates for the PS3 and 360 versions and one of the added features is new characters to play as. Perhaps one of them is Vader, but I am not sure.
srry no but you can be storm troopers and even proxy
use cheat code SITHLORD
No, he was only in IV.
He didn't have one. Luke has an apprentice during The Clone Wars: Asoka Tano
the last character is starkiller (the apprentice) in his sith stalker armour. In order to obtain this character you must play the last mission on the death star and instead of attacking the emporor when you have the chance attack the already beaten Darth Vader. this will start the alternative dark side ending where starkiller becomes the emporors apprentice and gets life sustaining armour like Darth Vader.
you can because when you got the game look on downloads and you see Darth Vader is 400 Microsoft points.