Much of the computer jargon used in this story has no real meaning and it's unclear how what's happening relates to a computer simulation.
The villain of this episode is called Devon Marek. His toy company is called Karem, which is Marek backwards and alludes to the highlander tradition of villains who have names beginning with the latter K.
In flashback, Duncan refers to his teacher Connor MacLeod, the central character of the first three Highlander films.
In flashback, Duncan meets Marek when he first dies and discovers his immortality but Duncan is confused that he was unable to recognise Marek as an immortal, as Connor taught him he would be able to do. This implies that Marek is the first pre-death immortal that Duncan has met. This is an issue that has been handled inconsistently across the series and Duncan's confusion might reflect that it is an inconsistent phenomenon for immortals.
At approximately the 38 minute mark, an office of a toy company is entered. On a shelf by the window in between a vase and a plant, two action figures from "Highlander The Animated Series" can be seen. They are still in package, on the left is hero Quentin MacLeod with Sword Slash Action, and on the right is Malone "The Human Key," with Power-Flip Action.