But! As he arrives on set, news breaks that aliens are out on the Strip at a Duke-themed burger joint and the blanket coverage from TV stations has forced the show to be cancelled. (Confused younger readers may wish to Google "We interrupt this programme" in order to understand what happened in these situations prior to BBC News 24 and Kay Burley's helicopter.) The game instructs you to divert to the "Duke Cave" for a briefing with the President and General Graves, commander of the Earth Defence Forces.
As expected, the aliens drop their peaceful pretence and come looking for Duke. At this stage he has to fend them off with his bare fists, and the game uses the slow start to introduce mechanics - such as the concept that consuming beer "makes you stronger".
(When I do this, the screen goes so blurry that it's impossible to fight and I can't work out if my strength has actually increased. But I suspect it has, because in a game where you can enhance your health by punching a "douchebag" in the face, it's hard to imagine any of the events that occur are cautionary rather than literal.)
You can also scoff steroids to make yourself go berserk, and at some point the lights go out, so it's time to use "Duke Vision" to see in the dark and take out aliens as they flail uncertainly into the gloom.
In Duke's nearby gym you can boost your health by bench-pressing a pile of weights, throwing a basketball through a hoop (assuming you can decipher the peculiar physics) and playing pinball. A pattern is established at this point: move through an area by killing all the aliens, probe the margins for secret bonuses and jokes (like glimpsing a pair of naked women through an air-vent, writhing and luxuriating on a bedspread), and solve the occasional puzzle.
The puzzles are welcome. As Duke tries to power up his casino so he can take on the mothership, a sexy female computer voice tells him he has to locate three power cores. Two are lying nearby, but the third is on the other side of bulletproof glass in a room full of crates and a toy monster truck.
Seizing the remote control for the truck, Duke has to manoeuvre it up some ramps and around shelving units to dislodge the power core and poke it through a hole in the floor for retrieval. "You sure know how to turn a girl on," purrs the computer, as he inserts the final core.
With the old lady up and running and the mothership waiting outside, it's time for a bit of girl-on-girl. Duke hops in a turret and rides up to the roof, where he proceeds to blast the alien ship with endless rounds while it fires a cannon at him and spits out dropships.
They prove no match. "Rest in pieces," Duke offers as the alien saucer disintegrates and ploughs into the Vegas skyline. (That "girl-on-girl" thing was my joke, by the way - I'm trying to get into the spirit of things.)
As he works his way back down through the casino, Duke is reduced to a tiny, helium-voiced Duke Shrunkem. Apparently his impact on the ladies is undiminished, however - "I know just where I'd put him," a young woman remarks as he passes.
Duke then encounters a child (who fortunately does not automatically want to have sex with him), from whom he borrows a toy car that he drives around the crumbling casino, jumping gaps and revving past oblivious alien swine.