Visible crew/equipment: When Yar and Worf prepare to cut through the wall beneath the capital city, you can see the flash-powder cord before they shoot and the phaser beams get F/X'd in.

Other: About two minutes into the episode, in a scene where Riker and Picard go to meet admiral Jameson in the transporter room, just as they are about to enter the turbolift Picard opens his mouth really wide as if making a funny face to someone inside the turbolift. Although it was filmed from the side it is quite easy to spot.

Other: In the opening (just before the title credits roll) Picard and Riker walk to the right of the screen to exit the bridge. Watching Picard's face it is clear that Patrick Stewart has taken over (clear break in character). He seems to be making an open mouth "face" (silent scream?) to someone off camera.