The designs look like they're designed for an old mobile phone rather than the original Game Boy itself. And if that's not insultingly enough, there's a lot more where that came from, along with the company name.
It was nothing more than an add-on for the Game Boy, just like the accessories that the Game Gear has, only except it's a little bit bigger than this piece of garbage. And to add insult to injury, this was expensive back in its older days.
The accessory is easy to break off, making it a complete waste of money to produce, forcing you to buy another one if you want to use it.
Some parts of the accessories could strain your eye vision just like the Virtual Boy, which also shared the same problem with the Handy Boy.
Instead of having it's own power source, it taps into the Game Boy's power via the DC input, but since it's an input rather than an output, it just shuts the Game Boy down instead since the Game Boy thinks that the Handy Boy is charging it but it isn't. The only other way to power it is to use a weird metal pronged contraption by taking the battery cover off and sandwiching the prongs between the batteries and the battery connectors, which doesn't work all that well.
It was quite decent as an accessory as the original just couldn't keep up, especially at nighttime where it may require you to get some lights to play on your Game Boy at night.
It works with the Game Boy Game Genie and Game Boy Camera since it doesn't block off the cartridge slot.
Unlike a lot of the Game Boy's accessories, this one doesn't require extra batteries, compared to the Booster, one of another Game Boy accessories, though not by STD.