You can now play 'Doom' inside 'Doom II'
 

Doom is playable on just about anything, from a DJ controller and Canon printer to an ATM and Minecraft. YouTuber kgsws took the Inception route, though. They put a playable version of Doom inside Doom II.

They used an exploit in the DOS version of Doom II, as Gizmodo notes. The modder, who explains the process in a 15-minute YouTube video, was able to get a modern port of Doom (Chocolate Doom, which uses the original source code) running inside Doom II as an animated texture. The original game is projected on a virtual display in a custom Doom II map that kgsws created.

https://www.engadget.com/run-doom-in...5.html?src=rss