Complex sentence: The song Chrome Invader was originally called Silver Surfer but had to be changed due copyright reasons; another song-Manhattan Martian-was supposed to be on the Independence Day soundtrack but didn't make the final cut.
Split into simpler sentences: The song Chrome Invader was originally called Silver Surfer but had to be changed for copyright reasons. Another song, Manhattan Martian, was supposed to be on the Independence Day soundtrack but didn't make the final cut.