Unfortunately, playing on its keyboard is not very comfortable.
I've decided to do something about it...
I've built a gamepad that connects to the usb port and fits nicely over the keyboard.
It features 8 buttons and a PSP joystick, the device emulates a USB keyboard so it works out of the box with all games/programs.
At the heart of the gamepad is an ATmega8A running V-USB software USB stack.
Video of it in action:
Schematics, board and code: