Programming "to the metal" is a VERY different experience and one that can be satisfying much in the same way that baking your own bread (flour, water, yeast..) can be.

Now the Gameduino abstracts a lot so maybe it's bad comparison; one is not doing opcode/cycle counting to time refresh rates of NTSC signals!

However, if you WANT to do something like that... http://nootropicdesign.com/hackvision/

One of the draws of arduino for me is that it by its very nature invites frankenstein type arrangements of hardware.

Just because this thing is old school tech, doesn't mean the peripherals people connect to it will be. Accelerometers are very popular in the arduino world. It wont be long before somebody manages to get their pets to interact with it somehow as well, that seems a strong meme in arduinoland.

Yes you can interface all these things to a PC as well, but there are many layers of abstraction imposed on you. And you don't get to fashion your own casing out of things you find lying around.

The entertainment value possible in consumer hardware that is produced with no profit motive whatsoever is pretty epic.

I imagine the potential of the arduino analog inputs means you could create some pretty novel interfaces for the games (i.e. beyond joystick and buttons)