Simplify the following text for a Grade 5 native English-speaking person.
Original: Wii Sports , a major factor in the Wii 's worldwide success , was the first release among a number of core Wii games being developed at the same , with the same philosophy ; others were released as Wii Play , Wii Fit , and Wii Music . A direct sequel to Wii Sports , titled Wii Sports Resort , was released in 2009 .
Simplified: Wii Sports is a sports game made by Nintendo for the Wii system .