Complex sentence: Ely, however, overshot his mark, coming in too soon, before the restatement of the riff; he realizes his mistake and stops the verse short, but the band does not realize that he has done so.
Split into simpler sentences: Ely, however, overshot his mark, coming in too soon, before the restatement of the riff. He realized his mistake and stopped the verse short, but the band did not realize that he had done so.