According to Brannon Braga, The Adventures of Captain Proton holodeck program was influenced by Flash Gordon. Versions of the program also appear in Thirty Days (1998), Bride Of Chaotica! (1999), and Shattered (2001). In the prequel Cogenitor (2003), a title called "The Bride of Chaotica" is one of the movie options for the crew's movie night, indicating that the holodeck program is an interactive version of a (fictional) movie.
The game that Paris and Torres play in the mess hall, referred to herein as "durotta," has game pieces that are easily recognizable as pieces from the real-life game Quarto. While playing the game, the characters follow the rules of Quarto, as well.
Neelix orders Bergamot tea from the replicator to calm himself while hyperventilating, saying "Bergamot tea, hot." This mirrors Captain Picard's preferred beverage throughout Star Trek: The Next Generation (1987), as oil of Bergamot is the defining ingredient in Earl Grey tea.
First appearance of the "Captain Proton" Holodeck Program.
As setup to the episode Seven of Nine explains the nature of the 2 year long journey through the void, and why they see it as a completely black space because it is filled with "Theta Radiation". This is convenient plot sci-babble since radiation of any kind does not occlude other radiation, like visible light, from passing through it. While it might occlude "sensors" since we don't know how the physics behind this future tech works so that might be plausible, but nevertheless we should see stars through the void. There are indeed inky black regions of dense dust concentrations which really are opaque seen from Earth such as the Northern and Southern Coal sack nebulas, which would have been a more plausible explanation, which wasn't used for some reason perhaps because it would have caused other issues with the plot.