A friend of mine had one. The worst part was that it had no charge. So the portability factor was pretty much wasted. A 40 dollar game would also cost however much 6 DC matteries cost back in the day, unless you were taking a road trip with your parents and invested in a cigarette lighter charger. Shit would crap out in less than 30 minutes unplugged. But I recall the graphics pretty much being Genesis quality.

I had this 6lb battery that screwed into the back. Lasted about 2 hours.