Ensure the keyboard to gamepad mapping is identical to your settings in USB Overdrive.For each button, select it and then enter the corresponding keyboard key in the field to the right (this shows when "Press Key" is selected in the drop-down box) Tap each button on the gamepad once to ensure all keys are on the list.Ensure the "Enabled" Checkbox is checked.Select my SNES emulator for Application.Select "New Duplicate Settings" in the top drop-down box.Select "Any Gaming, Any Application" from the top drop-down box.It was a bit tricky, as I had to go into my emulator and change the keyboard configuration to match what I was doing in USB Overdrive. I gladly paid the $20 once I got it working correctly.
The developer asks users to pay $20 for it, but you can download and run it for free if you're willing to wait 10 seconds each time you run it. This is a plugin for System Preferences that lets you detail what each button does, and ensure that it only applies to particular applications.
However, I'm sure it's pretty much identical to other brands of NES/SNES USB controllers out there. If there is another sub I should check out please point me in the right direction. If anyone knows of a nice USB controller that would be helpful as well. I have an old Mac Mini that Id love to turn into an intro-video game system for my 4 year old son. I found a solution! For the record (and for Google search results' sake), I'm using the GTron (G-Tron) USB SNES controller or gamepad. Im looking for a good NES/SNES/SEGA/Whatever emulator for OS X.