Simplify the following text for a Grade 7 native English-speaking person.
Original: Call of Duty : Modern Warfare 2 ( or Call of Duty 6 : Modern Warfare 2 ) is a first-person shooter video game developed by Infinity Ward and published by Activision for the Xbox 360 and PlayStation 3 video game consoles and the Microsoft Windows operating system .
Simplified: Call of Duty : Modern Warfare 2 is a first-person shooter video game .