Yeah, same issue here. I coated the thing with Novus plastic polish and it does help quite a bit though.
So after some more playing around with the RetroDuo, here are some more observations:
- My Tototek SNES flash cart works just fine with it
- PowerPak sram load/save works fine
- I have a Super Mario World cart that does not boot at all on the RD. Oddly enough if attached to a Game Genie, it works fine
- My Rolling Thunder cart will not boot/run properly on the RD, but the same game loaded from the PowerPak works fine
- My Dragon Warrior cart will not boot on the RD, but will work fine if attached to the NES Game Genie
Overall I am very pleased with the RD. It does seem to have some odd sound issues that the Yobo/FC didn't have, but the NES compatibility overall is better.
I've had extensive experience with other clones such as the NEX, Yobos, FCTwin, Blade, Power, etc. and though still imperfect, I proclaim the RD King of the Nintendo Clones!