Right, now that I've tried it out, it just so happens that the trainer does require an internet connection to start up, so there's no reason to explain how to download it (though I assure you it's very easy and requires no externally downloaded applications). Unless there are concerns with making the game more exploitable, I don't see why zanzarino wouldn't take off this requirement.
Also, to answer your question about "port[ing a .swf] to PC", note that you can open any .swf file with a browser.