While riding in the turbolift with the sick boy's brother, Data reaches over to the right side of the door and indicates a new destination. The control panel on the turbolift did not exist in the three previous seasons, and it was never seen again.
In order to lock out the ship's functions, Data inputs a very long code. The next scene shows the data stream on the console with some numbers missing or different. (DIfferences below in capitals.)
What Data says:
One, seven, three, four, six, seven, THREE, two, one, four, seven, six, charlie, three, two, seven, eight, nine, seven, seven, seven, six, FOUR, three, tango, seven, three, two, victor, seven, three, one, one, seven, eight, eight, eight, seven, three, two, four, seven, six, seven, eight, nine, seven, six, four, SEVEN, THREE, six, lock.
What the console says:
One, seven, three, four, six, seven, two, one, four, seven, six, charlie, three, two, seven, eight, nine, seven, seven, seven, six, three, tango, seven, three, two, victor, seven, three, one, one, seven, ONE, eight, eight, eight, seven, three, two, four, seven, six, seven, eight, nine, seven, six, four, THREE, SEVEN, six, lock.
Data has always been deemed unable to use elisions (contractions). However, while imploring Dr. Soong not to reactivate Lore, he uses "would've" in describing Lore's behavior.
It has been established that Data can and occasionally does elide words and phrases but, presumably, chooses not to because of punctilious and pedantic delivery, for the sake of linguistic accuracy.
When Geordi, Riker, and Worf are on the transporter pad, beaming down to the planet, their reflections remain on the transporter pad ceiling after their bodies have disappeared from the pad.
As Dr. Soong asks Data for the reason why humans are so fascinated with old things, Brent Spiner's real skin on his right hand can be seen shining through underneath the "old man" gloves.
Data starts a blue alert on the Enterprise. The original blue alert shots were achieved by turning on the red alert lights, and then altering those lights to blue in post-production. The remastered version forgot to change one shot, so the original red lights briefly show up on the bridge when Data is alone.
After the command crew has returned to the bridge, the camera pans past Captain Picard and the zipper pull on the back of his collar is visible.
Given that the entire command staff is in Main Engineering, standing next to the warp core, there would be a number of ways to physically disable the engines and stop Data, such as manually blocking power to the warp engine, disrupting the fuel flow into the intermix chamber, or simply by opening the hatch and removing the dilithium crystals. None of these options are ever discussed, with La Forge simply saying that they have no computer control.
Data requests the Enterprise computer to show him the fastest route to a transporter room. As an Android, Data would not need to ask this as he would have 'memorized' the full schematics of the Enterprise.