The position of Sybilla's fingers on the mirror/compact while powdering her face change between shots.
The space cropper's ship having taken off does not look anything like it did on the ground. In fact it looks the same as the space pirate A.P. Tucker's ship and Travelin' Man's ship from earlier weeks after takeoff.
Will heads directly to the croppers ship to warn Dr. Smith, but doesn't know Dr. Smith is inside the Jupiter 2 packing. When Maureen comes upon Dr. Smith while looking for Will, Smith then announces his forthcoming marriage to Sybila then leaves. When Will gets to the croppers ship, Smith is there well ahead of him and sweet-talking Sybila, never having passed Will on the way there.
When the werewolf reverts back into Keel, its footprints revert from wolf tracks to shoe tracks instead of to footprints from the bare feet they should be.
Dr. Smith is shown packing his suitcase before leaving to go join Sybilla at her ship. But Dr. Smith was an accidental stowaway on the Jupiter II, and he wouldn't have a suitcase to pack.
When Will and Dr. Smith first walk into the Space Croppers' camp, the boom mike clearly maneuvers in overhead for a few seconds.