Simplify the following text for a Grade 5 native English-speaking person.
Original: On release , Halo 2 was the most popular video game on Xbox Live , holding that rank until the release of Gears of War for the Xbox 360 nearly two years later .
Simplified: Halo 2 was the most popular Xbox Live game on its release . It held that title until the release of Gears of War nearly two years later .