This is the programmer who works on the pretty effects, with the new generation of consoles this is basically a full time job for more than one person, but don't think it's easy, you'll be spending hours optimising your pixel and vertex shader code to squeeze that last cycle out and get one more character on screen; having to bend over backwards for the artists to try and get your shader that worked wonderfully on your test cube to work on their polygon soup; having to work tightly with the tools team, perhaps even writing a few tools yourself so the artists can actually use your effects in game.

But it's not all bad, this is probably the most visually rewarding of all the technology programmer variants as you'll actually be able to tell people, "See that shine on that pole, I did that!", for some reason this is preferable to saying "Look, you can load save games when you put your memory card in!"

Unlike all the other programmer types, you'll need to have an eye for graphics, and you'll need to be able to work closely with artists to create the effects they want. As for a demo, the most impressive we've seen usually consist of an environment you can move around (either by walking or flycam), with various cool effects applied throughout done in a nice integrated manner. A floaty cube with a bump mapped texture on it is not going to get us excited.