Complex sentence: By July 31,2008,20 days after its initial release, the game approached 1 million downloads whereas the installed iPhone OS 2.0 user base was 5-6 million.
Split into simpler sentences: By July 31,2008,20 days after its initial release, the game approached 1 million downloads. The total installed iPhone OS 2.0 user base was 5-6 million.