In every episode, after the opening credits a quote appears on the screen that will be spoken by a character in that episode.
The opening song is the same, but every season a new version is used with different artists performing in different genres (blues, soul, etc.).
The opening credits of Season 1 feature visuals and clips of things that happened during the episodes of that season. Season 2 features clips from episodes of Season 1 and 2 Season 3 features clips from Season 1 through 3 Season 4 features clips from Season 1 through 4 Season 5 features clips from all 5 seasons. During these credits you never see anyone's faces. The credits also feature several listening and communication devices.