गूफ़

Several times, Scotty is drawn with a captain's extra braid on his sleeves.

At the beginning of the episode, Kirk order the Enterprise's shields up then orders Mr. Scott to beam the pilot of the scout ship aboard. It's been well-established that the transporter can't function with the ship's shields up.

Close-ups of Scotty operating the transporter clearly show a mustache sticking out from his face. This is actually footage of Mr. Kyle, the other transporter operator.

When Kirk talks to Koloth on the viewscreen, Koloth's entire body suddenly appears to be on the bridge of the Enterprise in front of the viewscreen.

Due to the use of stock footage, the bridge is infested with tribbles in one scene and tribble-free in the next.

When the Klingon weapon fails (trying to stop three ships at once), a subsequent bridge scene has the blinking lights on Uhura's console briefly appear *over* her face.

In The Trouble with Tribbles (1967), it is established that tribbles let out an ear-piercing screech when close to a Klingon; however, when beamed aboard the Klingon ship in this episode, they continue to purr happily.