Perhaps the ultimate meta-reference in 'Deus Ex' is to The Matrix's habit of inserting random references to other media, and the assumption that merely invoking names and concepts imbues the product with depth and meaning. Thematically, 'Deus Ex' is a combination of elements from 'The Illuminatus! Trilogy', 'Nineteen Eighty-Four', cyberpunk and conspiracy fiction, UFO lore, the aforementioned Keanu Reeves blockbuster, the persistent anime theme of rival brothers, the Nation of Islam's notion that AIDS is a tool of biological warfare, and the idea that governments create artificial threats in order to shore up their own power.

More tenuously the game uses the hoary device of using a wrecked Statue of Liberty as a metaphor for the damaged state of liberty itself, whilst, as in 'Illuminatus!', the underground opposition movement are implausibly well-organised and equipped, and morally untouchable. It is significant that the early part of the game penalises the player for wantonly shooting 'rebel scum', whilst in the latter part of the game, after having switched sides, the player is allowed to exterminate large numbers of government troops without adverse comment.

In terms of specific, unusual references, a hacked computer in a plague ship reveals the phrase 'Reindeer Flotilla', a passcode from the film Tron, another film which deals with the possibility that the real world is merely a turtle on top of an endless tower of turtles.

On a technical level the game contains a mysterious basketball, a minor trademark of the late, lamented Looking Glass studios which appeared in both 'Thief: The Dark Project' and 'System Shock 2'. Although 'Deus Ex' does not use the same graphic engine as the aforementioned the games share the same look, and in both games you can activate secret messages by dunking the balls through stategically-placed hoops.

And, of course, both the leather-trenchcoat-clad main character and the G-Men are lifted from 'The Matrix', the men in black based heavily on Hugo Weaving's dress and most notably speech pattern. Given that the villains from The Matrix were in turn based on the Man in Black from Half-Life, this is perhaps poetic justice.