Thanks goes to Speacry from www.youtube.com for sharing the information. 
The 3 different versions of BRS openings:
1. Black ★ Rock Shooter - Pilot Animation (Original / Instrumental) (0:00 to 1:40)
2. Black ★ Rock Shooter - Pilot Animation (2M Mix / Miku Hatsune voice β) (1:40 to 3:20)
3. Black ★ Rock Shooter - Pilot Animation (2M Mix / Instrumental) (3:20 to 5:00)
© Huke / B ★ RS Project
Official Site: http://www.blackrockshooter.jp/
Black Rock Shooter:
A blue-eyed girl. Her weapons is the Rock Cannon and the Black Blade.
Black Rock Shooter and Dead Master are sisters originally and the Black Rock Shooter has to kill her sister to a treason of this last one.
STORY:
Black * Rock Shooter is a story of two schoolgirls who are sisters. The "Black Rock Shooter" and the "Dead Master". The Black Rock Shooter wants to kill her sister after she was betrayed lately.
CHARACTERS:
1. Black Gold Saw:
A red-eyed, red horned girl. She carries a huge sword and appears to have a skeletal arm.
2. Black Devil Girl:
A green-eyed, horned girl. Her weapon is a sword.
3. Dragon Slayer:
A yellow-eyed girl. She wear a crown and her weapon is a golden long sword.
4. Dead Master:
It is the sister of the Black Rock Shooter. She betrayed her sister who wants to kill her lately.
5. Insane Black Rock Shooter:
A purple-eyed girl. It is the fusion of the Black Rock Shooter and the Black Gold Saw.
~Razi-chan
