Simplify the following text for a Grade 9 native English-speaking person.
Original: The game first started in 2001 as Runescape ( now referred to as RuneScape Classic ) , but the code and graphics engine was rewritten in 2004 to form Runescape 2 , the game that is playable today .
Simplified: Upon its official release , RuneScape 2 was renamed simply RuneScape , while the older version of the game was kept online under the name RuneScape Classic .