This guy manually programs Flappy Bird into the RAM of Super Mario World without using any external equipment (except a multitap).
He exploits a number of glitches that makes it possible to enter and run arbitrary code by just jumping and doing other seemingly random stuff at certain locations and time points in the game.
Here is the video:
https://www.youtube.com/watch?v=hB6eY73sLV0
That guy is awesome. I have seen a few of his snes injection videos. He is the 1st person I the world to manually pull off the credits warp glitch as well.
This is cool!
Awesome! This guy also managed to teach neural network called MarI/O to beat few levels of mario's games.