Well, I just googled "Gamby.h" and it turns out that Gamby is its own Arduino based little game toy device. It has four buttons and a d-pad, compared to Arduboy's two, and its screen width is 32 pixels fewer than the Arduboy.
While you did make an effort to find an Arduino game to use on your Arduboy, not all Arduino software is compatible with all Arduino hardware.
At least you didn't try installing an .exe
Try checking out the Games section: http://community.arduboy.com/c/arduboy/games