You know that your cookies, are just a file like all the others.
Literally go into your appdata roaming macromedia flash folder \ shared objects, pick the folder for the swf (it would be different on 4chan too, if there were multiple names for it, so seekt the one with your progress)
then you go into the 4chan folder and copy all the files.
Open the same swf locally in your browser.
Play the game and get a save.
Go into the same swf folder, but this time pick localhost not 4chan. Paste all the files.
Voila, you can now play the game anytime from your local disc. I think the path is important though, so put it somewhere it will stay and then open it for the first time.
I'm not going to explain how to save a swf file from inside your browser.