Back in 2015 we learned about a "Minecraft genius" who was hard at work building a working version of Pokemon Red in the game. It was "a rather ambitious project," its maker, Magib1 (now known as Mr. Squishy) acknowledged, especially since he was doing the whole thing by himself. He said at the time that he hoped to have the "core mechanics" figured out within three or four months. Now, 17 months later, it's finished.
The project took 21 months in total, according to an announcement posted on Reddit. It was built with 357,000 command blocks—no mods were used—and took 2,832.89 kilometers of in-game travel to complete.
"I have done my best to incorporate all of the original game's features, along with a few iconic bugs (most notably MissingNo/'M and item duplication)," Mr. Squishy wrote. "I chose not to add any sounds to the game, as I fear there would've been too many desynch issues distracting from the game itself." As for why he put this much work into it, he continued, "I love pushing the boundaries of the game. Minecraft really shouldn't be able to run Pokemon Red—it's a 3D game about building and surviving—but the fact that it can is excites me. It truly shows that if you can dream it, you can make it."
While those "iconic" Pokemon Red bugs were duplicated for the sake of authenticity, Mr. Squishy warned that the map is bound to introduce some original bugs of its own, too, and so urged users to make regular backups "so that you can revert if you encounter any issues." He also said that players should save the game in the start menu before logging off, as logging off "during dialog, menus, battles, or cutscenes" might break it, and to be sure you've got at least 2GB RAM dedicated to it. Download links and other details are available from the Minecraft Forum.