When on the floor right
after Spock gives Kirk the 'Vulcan Death Grip' you will notice that
his head moves while he is supposed to be dead. It was originally
facing to the side but the last time you see it his head is looking
up.
When Spock is making his
final statement, the Romulan Commander states that his 20 minutes
are almost up, though he started only moments before.
When the Romulans call
Kirk to have him transport over, Kirk looks directly into one of
those tri-screen displays in the briefing room. Because of the way
he looked he shouldn't be able to see the Romulan, or the Romulan
see him.
Captain Kirk lets the
(enemy) Romulan commander onto the high-security classified bridge
in the middle of a battle
Spock and the Romulan
Commander travel from deck 1 (the bridge) to deck 2 (her temporary
quarters), but they spend several minutes on the turbolift doing
so. Deck 2 is the science level. They should have gone to deck 4.
When the Enterprise was
escaping at the end, the space sensor array was off.
At the end, the Enterprise had only
the left warp nacelle.
The Romulan cloaking device,
which Captain Kirk and Mr. Spock risk everything to steal, would
later be loaned to the Federation for use aboard the U.S.S. Defiant
in the Gamma Quadrant on
"Star Trek: Deep Space Nine".