Speedrunners learn to do amazing things to games. They discover glitches and exploits that allow them to change the way titles can be played. Sethbling is among the best, and he used his skills to do something special to Super Mario World. He made it into Flappy Bird .
SethBling made the transformation happen with a standard Super Nintendo, ordinary copy of Super Mario World , a multitap, and multiple controllers. He made the game glitch, then used a created bootloader to add code written by P4plus2 into the system memory with multiple controllers to make it into Flappy Bird. MrCheese also helped with the project, finding the arbitrary code execution.
You really have to see Sethbling show how everyone made it happen. It’s fascinating. This is absolutely extraordinary. That is quite an exploit. Well done, SethBling, P4plus2, and MrCheese. You did something amazing.