I remember something about this game when I cracked it myself, I believe it loads some data into the screen/colour area ($0800-$0FFF) which I think contains data for the graphics of the banners. I will try and check it out as I still have the original hack tape I did and a Plus 4!!
If anybody wants to correct me on this then please feel free, it has been a long time :-))
Lando, also your site is topz, I was going to do my own site with games etc, but I think I'll just scan covers and send any files I can to yours, if thats ok, I believe I have the original Summer Events tape still, so will try and send scanned cover for you, OK??