Simplify the following text for a Grade 7 native English-speaking person.
Original: Call of Duty : World at War is a first-person shooter video game developed by Treyarch and published by Activision for PC , PlayStation 3 , Wii , and Xbox 360 .
Simplified: Call of Duty : World at War is a first-person shooter videogame . It was made by Activision for the Playstation 2 , Playstation 3 , Nintendo DS , Xbox 360 , Nintendo Wii and on PC .