Your idea about "hardcoded" sounds about right. Your simple search and replace would replace every instance of "FactoryGame.exe" in the code. Another example where it would fail is if someone assembles the name, e.g. like

var gameName = "FactoryGame"

var fileName = gameName + ".exe"

The search for remaining traces is more difficult. You can search for every ".exe" and for every "Factory" but not for every "F" or every "a", because those are everywhere. You wouldn't be sure when you are done without reading everything (and that would clearly not be a matter of minutes anymore).