
There are Chinese NES based handhelds out there with a ton of games on an actual cartridge-sized cartridge and an overall physical footprint of a Gameboy Micro. Looks like he built a housing for controls, a Battery, a small LCD TV and a port to bring all the connections out, and then mated a couple of full systems to matching connectors and called them "cartridges".
These type of hacks are very cool when they accomplish something that couldn't be done before. This one sort of smacks of someone who is only marginally skilled and simply had too much time on their hands.

RandyT