Did you make sure you were using NTR 3.3 or higher. Using the older versions(3.2 and below) causes the top screen to clone to the bottom. Also, you press select to access the cheat menu on Ryan's plugin.
Made an account just to respond. I'd love to test codes, I've been waiting for these type of codes since the game came out. Thanks for bringing the glory days of City Folk hacking back.