When Wesley leaves to setup the probe for the modified neutrino beacon near the end of Act One, his position is taken over by another crewman as Worf picks up the transmission from Tomalak. At the start of Act Two when Picard has Worf hail the Romulans, there is a shot of Data AND Wesley sitting at their positions as Picard talks to Tomalak. Two scenes later, Wesley returns to the bridge to tell Picard the probe is ready to launch and then returns to his position.
When Geordi falls down the hole, his VISOR lands on his right-hand side above his arm. When he comes to, he finds his VISOR on the left-hand side.
During Picard's first conversation with Tomalak, the status indication lights at the aft end of the bridge indicate that the Enterprise is at Yellow Alert. However, during their second conversation, the status indicator shows the Enterprise at its standard alert status. Being less than half a light-year from Romulan space, and having a Romulan warship close-by would warrant the ship being at Yellow Alert, so they would not have stood down to standard alert status.
Down on the planet the Romulan is unable to walk without assistance from Geordie. But after both being beamed to the Enterprise, the Romulan is seen walking without help to the turbo-lift.
Geordi makes the spikes to climb out of the chasm by melting metallic rocks in a crude finger-drawn channel, yet when he uses them to climb out, they are nicely rounded and finished.
The scene of the Enterprise & Romulan Warbird departing Galorndon Core is reused footage of Enterprise & Romulan Warbird Haakona departing Iconia in the Season 2 episode 'Contagion'.
When Geordi falls down the hole, he hopelessly tries to call out to the rest of the landing party. A far better idea would be to shoot his phaser up through the hole -- the light beam would have acted like a signal flare.
When Worf is considering whether to donate some of his cells to the Romulan he decides to speak to the Romulan, Worf tells the Romulan the only way he will live is by getting a transfusion of his cells, upon hearing this the Romulan says that he would rather die than accept a transfusion from a Klingon. Yet after this Dr. Crusher and Captain Picard still try to convince Worf to be a donor, even though the Romulan has refused to accept Worf's cells. Giving him the transfusion against his wishes would violate medical ethics, the wishes of the patient are always respected by doctors, even if that means the patient will die. This is a core tenant of medical ethics and there have been numerous times where Federation doctors, including Crusher, have stated that they cannot treat a patient against their will.
Why couldn't the Enterprise separate and leave the saucer section there to get Geordi, and the hull section take the Romulan to his people? To avoid war and to save a life, wouldn't this make sense? If they didn't want to split the ship, maybe leave a shuttlecraft? They have transporters as seen later in the series.
Deanna speaks about how there is great hostility behind Tomalak's smile. But he is across the neutral zone, 6 hours away by warp from the ship. Too far away for her to insight anything using telepathy.