To be honest, this probably would have been a lot easier to implement as a UberASM script rather than a standalone patch, since you could just run it in the level you wanted to run it in, and without worrying about freespace or overwriting existing code:
https://www.smwcentral.net/?p=section&a=details&id=19982
But it's a neat idea nonetheless, and works well either way.
Somewhat disappointed. I was expecting them to use the well-known arbitrary code execution exploit in this game to load their own implementation of FizzBuzz, cf. https://www.youtube.com/watch?v=OPcV9uIY5i4
The method used by Masterjun3 is TAS-only (it involves executing the contents of the controller registers as code, which requires frame-precise inputs), but there are some other methods which are more viable for a real-time attack.