Simplify the following text for a Grade 8 native English-speaking person.
Original: On November 11 , the Left 4 Dead demo was made available to all Windows and Xbox 360 gamers worldwide . The Left 4 Dead demo was removed from the Xbox 360 Marketplace and Valve 's own Steam after the game 's release on November 18 , 2008 , however it is still available for those that played it .
Simplified: Left 4 Dead is a first-person shooter video game made by Valve Corporation for Windows and the Xbox 360 .