Guard Down - Kelly Bailey  
From the game Half Life 2 Episode 1 
  
Main Riff: 
G |-------7---------------|7-----7------8-------7---| 
D |---0-------0---8-------|---0-----0-------0-------| 3x 
A |-----------------------|-------------------------| 
E |-----------------------|-------------------------| 
  
G |-------7---------------|7-----7------------------| 
D |---0-------0---8-------|---0-----0---7---6---8---| 1x 
A |-----------------------|-------------------------| 
E |-----------------------|-------------------------| 
  
(This riff plays throught the whole song with different variations)