The Power Joy Voyager does everything the original Power Joy can do, with the bonus of having 9999 different Tetris clones as well, if you can consider that a bonus. This system has the unique ability to be powered by 4 AA batteries, unlike the original Power Joy, as well as allowing you to use the Game Boy style controller layout for single player games (While in "NES" mode) or plugging in a pair of controllers, which are tied together to a single DB9 end.
Although slightly bigger, the overall design is undoubtedly trying to resemble that of a Nintendo Game Boy Color, and at first glace thats what I originally thought it was. Even the cartridge has a slight Game Boy look to it, but more of a knock off Game Boy pirate design. Its comfortable to hold, but the built in games aren't really what will have you holding the system for too long, thats the built in NOAC.
On the very top are the (mono) AV outs, all you have to do is plug in your cables and flip the switch on the side from LCD or Off to TV and you have a tiny Famiclone. For the Famiclone part there are no built in games, the software comes from the PJ-007 cartridge. The cartridge shares the same name, and game list, as the Famicom style cartridge that comes with the original Power Joy.
Short of it having the 9999 LCD games, the Power Joy Voyager functions exactly the same as the Power Joy. I find this one to be more unique in design and a lot easier to shove in a bag and take on the road. Although they made different cartridges for the Power Joy, I believe the PJ-007 is the only one they made for the Voyager.