The circle is complete: we managed to run Doom… in Doom

It’s long been a dear challenge to nerds: running the venerable Doom game on every platform imaginable. But we can say that this time, we did the trick. Because a programmer has managed to achieve the ultimate hack, the holy grail for this small community with a strange hobby: running Doom… in Doom.

This small technical exploit, we owe it to a programmer who responds to the pseudonym “kgsws”. In a long and very technical Youtube video, he explains how he managed to run the old FPS in a map for Doom II that he created for the occasion.

And it was no small feat! After carefully analyzing the game code, he discovered an exploit allowing the execution of arbitrary code. He therefore made sure to load a second version of Doom into memory through this flaw. He then designed a map that displays the game through an animated texture.

Rather impressive, especially since it didn’t stop there. Since kgsws was able to run code in Doom, it also integrated several other games into the game: a minimalist version of the famous Snake, an Asteroid clone and even Heretic, another famous FPS from the early 1990s , which took over the engine from Doom.

The curious can download all this on the developer’s GitHub page, who still wants to remember that the hack only works on the original version of Doom II, because the code has evolved since then. And we must of course not forget that this rather special version requires twice as much RAM, given that two copies are running at the same time. However, this shouldn’t be a big problem for a modern PC, since kgsws estimates the memory footprint at 16 MB…

Doom, an open source game since 1997

Let’s be specific: this isn’t quite the first time that Doom has been playable in Doom. We can indeed also enjoy it in the much more modern Doom Eternal (2020), if we enter a secret code on a computer in the Fortress of Destruction. But hard to compare this pretty easter egg to the reverse-engineered performance of kgsws!

For years, the port of Doom has fascinated hackers, who have managed to run it on ever more improbable platforms. It must be said that the title combines the advantages for this, beyond its status as a cult game: it was written in C, a very widespread language and with an easy-to-port code… Above all, John Carmack -the creator of the game- made its code open source in 1997which allowed hackers to appropriate it.

Since then, Doom has been seen running on scientific calculators, the Apple Watch, drone remotes, the new Game & Watch, and even Minecraft. Beyond the fun challenge, it’s also a real symbol. Because launching Doom proves that you have total control of your computer tool. Which is good to defend, at a time when hardware manufacturers are increasingly locking down their devices.

Source :

Youtube