Complex sentence: The remastered version contains a note on the inlay that explains that the sound of the album is less polished than their newer work, in part due to time constraints as well as heavy drinking.
Split into simpler sentences: The remastered version contains a note on the inlay that explains why the sound of the album is less polished than their newer work. According to the inlay, it was in part due to time constraints as well as heavy drinking.