a comment on that site really condescendingly claims this is how he would have handled it and that a script could be written in half a day to do the work.

my understanding is that an emulator effectively recreates the hardware’s different components in software so that from the game’s “perspective” it’s running on a real machine more or less.

This process instead decompiles the game code and recompiles for a new target machine.

I suspect one can’t just pump out a script in an afternoon to do this, but I am curious what is the complexity here?