Snes8x for Windows Phone 8 runs well, judging by user comments, and all screen resolutions are supported. Unfortunately, the emulator isn't compatible with Windows Phone 7.8, but hey, think of it as another reason you should consider upgrading to something newer. Oh, and before we forget, loading whatever ROMs you may have is a bit of a ritual, but doesn't require much technical know-how. You are required to load them via SkyDrive, but once they are in the database, launching one should be pretty straightforward.
Snes8x is available for free on the Windows Phone Marketplace and you can download it from the link below.
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