Simplify the following text for a Grade 7 native English-speaking person.
Original: World of Warcraft has had multiple expansions , namely World of Warcraft : The Burning Crusade , World of Warcraft : Wrath of the Lich King and World of Warcraft : Cataclysm .
Simplified: The MMORPG World of Warcraft is based on these games . Blizzard Entertainment also created World of Warcraft , which was published by Vivendi Games .