This was the pilot episode of the series. One of the most notable differences from the series is that Inspector Gadget sports a mustache, which was dropped in later episodes because it made him look too much like the trademarked likeness of rival MGM Studios' character Inspector Clouseau (animated version).
Frank Welker did Inspector Gadget's voice in the scene where Penny compliments his mustache, Don Adams was unavailable for the re-recording so Welker filled in for him.
Penny and Chief Quimby were voiced by different people in the pilot.
In most territories, this pilot episode was broadcast at the very end of the first series run (as episode 65), or not at all.
Through out the series the same mad agents get arrested over and over in almost every episode.