It is made out of a really strong plastic that isn't creaky or cheap feeling. Of course the Game Buddy does add some weight and bulk to the Gameboy, but it is still comfortable to hold. I doubt if it would fit. When the Gameboy is in the Game Buddy, none of the controls are obstructed. You can still plug in head phones, adjust volume and contrast etc.
Games are still as easy to insert and remove as well.
The Gameboy Pocket slides into the Game Buddy easily and is held in place by two clips and a metal power prong that fits into the AC adapter power port on the Gameboy Pocket. Once the Gameboy is inserted, the Game Buddy is a snug fit and there really isn't a danger that it will fall off. I have always hated buying a new gizmo like a cordless phone or something and not be able to use it till it's charged. With the Game Buddy, it's already good to go. These type of batteries last 10 times longer than regular disposable cells, can sit unused for up to 5 yr. without losing power.