Errores

As Nyota states that the time for the cease fire is coming to an end she said that there is 2 minutes left. Then 14 seconds later she says that 2 hours have passed. Clearly not 2 minutes.

In his log entry, Pike refers to the Romulan vessel as a Bird of Prey. This is a Klingon designation, while the Romulan analog would be Warbird. As Starfleet has, up to this point, little-to-no knowledge of the Romulan species or culture, they do not know the term Warbird. Pike recognizes the similarity to a Klingon ship and uses the term out of convenience. A crewman in Balance of Terror (1966) remarks that Romulan ships are known to look like huge birds of prey.

Uhura informs Pike that the closest Federation ship, the USS Farragut, is a couple of hours away. The Farragut then arrives only a few minutes later.

Explanation: It would have been a few hours away by standard warp. When he arrives, Kirk says that they pushed Warp 9 to get there.

In Balance of Terror (1966), the commander of Starbase 4 is Hansen, but now his name has been changed to Al-Salah. Al-Salah's first name is Hansen.

Several characters make reference to blowing ships "out of the sky." The ships are in deep space. "Sky" refers to a visible upward view from a planet's surface, usually specifying within a planet's atmosphere.

It's a figure of speech. Just like Ortegas' earlier comment that she'd keep her "foot on the gas".

The size of the shuttle seen leaving the Enterprise is incongruous with the scale of the two vessels. The shuttle would have to itself be several decks high and many times its normal length to appear as large as it is seen here.

Pike states that the Enterprise is holding to its side of the Neutral Zone, yet acknowledges that they are surrounded by Romulan ships. As the Neutral Zone is many light years across, both cannot be true. Were the Romulans holding to their side of the Neutral Zone, they would not even be within visual range of the Enterprise.

It's the Romulan Praetor who says that she has the Enterprise surrounded.

As in the Original Series "Balance of Terror", after the Romulan Bird of Prey destroys Outpost 4, you can still see the image of the Bird of Prey on the view-screen as it engages the cloaking device, even though this was AFTER the outpost had been destroyed, supposedly taking the camera with it.

The Menagerie: Part I (1966) explained that Christopher Pike was in his horrible accident a few years after leaving the Enterprise. In "A Quality of Mercy" it is implied that he was Captain of the Enterprise at the time of his accident.

Uhura is supposed to be a language expert, yet she mispronounces the word "praetor" twice, saying it as if it rhymes with "creator."

When hailing the Romulan vessel, Pike says that their cultures have been "at war" for a hundred years. The Federation and Romulan Empire are in a state of cold war, not an actual war. The entire purpose of the Neutral Zone and the treaty that established it (mentioned earlier in this episode) is to facilitate the co-existence of the two cultures, even if the peace that the treaty grants is uneasy and delicate.

Captain Pike is a friend of James T. Kirk's older brother George Samuel Kirk, but still asks James Kirk where he's from.

Helmsman Ortegas sits in the wrong seat yet again. Her "drivers seat" is on the left (port), not on the right (starboard) where Ops is. There is no logical explanation to Ops being switched with Helm such as damaged controls or otherwise. Makes as much sense as putting a driver of a car in the passenger seat next to the drivers.

When Kirk first addresses Spock he does not recognize him, as they have not yet met in this timeline. But Kirk addresses Spock as commander, although Spock is standing at ease with his arms behind him and the rank on his cuffs hidden.