At about the 2 minute mark, Henry is carving the words "DR. NATHAN STARK" into the archway with a laser. He has carved "DR. NATH" and is actively finishing the 'H' when Fargo tells him to stop. Fargo questions the size of the lettering. While that occurs, there is suddenly a second 'A' hidden behind Henry's head, even though Henry never lased it.
At about 30:44, when Carter is on the radio, a bug is walking sideways across the screen in front of him, as if it were on the camera lens. You can also see bugs walking on the screen at 30:36, in front of the greenery on the right side of the screen below the roof line.
When they trap the plague in the freezer at Cafe Diem, Vincent types in -273 degrees Fahrenheit and says it's absolute zero. Absolute zero is zero Kelvins or -273 degrees Celsius.
Vincent says zero degrees Kelvin, when the correct label is zero Kelvin, the word degrees is not used for the Kelvin scale.
Nathan Stark Shows up when light hits a diamond necklace. Yet, His fiancee Allison had to turn on a lamp light to be sure it was him the very first time. Any other time (out or inside) he showed up he was clearly seen.
In short, outside or inside, the Nathan ghost imagery was clearly seen, but not in Allison's office at night.
In short, outside or inside, the Nathan ghost imagery was clearly seen, but not in Allison's office at night.