Now I didn't have any problems playing Sega Genesis games plugged into it (the Retrogen includes a few built in but they're so dorky you can forget about them). I've been told that is because the Retrogen uses emulation technology rather than a direct cloning of the Sega Genesis game console's hardware. Regardless, all I can about is that it worked.
And when I put in Michael Jackson's Moonwalker and started moving him and the chimp Bubbles around the scrolling game screen, I felt like I was back living in my loft in New York city in the good old days again. The smoothness of the animation and the graphic renditioning and the sound was all I had hoped for. And it's what I got.
I also insist you use a headphones so you can appreciate and enjoy the Dolby stereo sound. Granted that the synthesis of the audio is a bit funky, but frankly that's one of the signature charms of the Genesis game console and now it can be up close and aurally personal when playing the Retrogen.
I should probably mention that a few games have been built in and so can be played immediately upon turning the Retrogen on. You should consider these more as tutorials for how to work the various game controllers and for getting into a "16-bit" mood - the games are pretty basic and far from exciting. But they are free. More importantly, they'll make you want to go and get some really good Sega Genesis game carts!
Innex