All cinematics in Star Wars: The Force Unleashed II are available from the start. There is no unlock requirement.
VADER – Darth Vader skinMAREK – Starkiller (TFU1) skinWHITE – White Lightsaber crystalBLACK – Black Lightsaber crystalIf a cutscene doesn't play, verify game files (Steam) or clear cache (Xbox 360: System Settings → Memory → Clear System Cache).