The steps are supposedly as follows: Insert a USB key with a single file containing the vehicle's VIN into the infotainment system's USB port and then start the car, putting it in debug mode. Stick a disc (a CD-ROM?) into the car's CD drive. Then choose the game through some sequence of button and screen presses. The car's controls (throttle, steering, shifter) magically turn into Doom controls and you're off.
If after you've watched this admittedly convincing video you're still not convinced it's fake, consider this: The hack is based on an easy trick that allows anyone to gain access to a car's computer's debug mode, requiring only a USB stick with a single file you can make yourself. Video dude explains that this is part of a recent trend of automakers opening up their systems so anyone can mess with them, except that basically the opposite is true: automotive systems are more locked down than ever and car companies are looking to keep you out at every digital turn. Then there's the fact the Porsche's infotainment screen shows a windowed interface in the fictitious debug mode, when the system underneath is more likely some flavor of command-line Linux. And the car's various controls being mapped to the ones you need to play Doom, with no setup? That's just silly. (When's the last time a new game controller "just worked" the second you plugged it in to a console?) Oh, and he calls it a "Porsch." One syllable. All credibility lost.
For those curious, the car in question is a 2017 Porsche 911 Carrera S Cabriolet, the one with the turbocharged engine. While it might look like Doom is being run on the Porsche Communication Management screen, it's probably been added digitally, with video roughly synced up to the driver's (sped-up) actions to fool you at the end of the video. We'd tell you not to try this at home, but really, go ahead and give it a go, because it's simply not possible. And if you believe this guy, who is obviously joking, this same neat trick works on just about any car. (If you do get Doom or any other game running on your car, first let us know because that's awesome and then absolutely do not drive around playing it, whether you're on public or private property.)
You might also notice a toaster precariously perched on the passenger seat. It's a callback to other toaster-hacking videos from the same user. They're also BS, but, if you're in the know, funny BS. Our hats off to vexal for perpetrating this clever prank and getting some people to believe it.