Really? I don't remember the part in Max Payne where I got to drive a car made out of squiggly light that turned into a rhinoceros.
And once you do start incorporating other elements like AI, level geometry, physics, etc to make things interesting, you'll no longer have the luxury of allocating all your computational resources for graphical eyecandy.
Smash of Fairlight who wrote the 2nd placed demo is in the games industry (at Sony Europe IIRC): http://directtovideo.wordpress.com/about/