This (and many other demos) run in 640x480, so fillrate is a non-issue.
This has just a few static object on screen. They are fairly high-poly, but many cards can handle a high poly-rate if it's static (and can fit in video mem). I don't know what you mean about "glow effect", but if it's the environment mapping, it can be done fairy well on a TNT with a few restrictions.
Non-descriptive graphics like this has the advantage above typical games that they aren't supposed to look like something special. So you aren't so critical about details, and things that are "wrong".
If you want the environment mapping in a game, you probably want it to mirror the actual world around it, instead of a static env-map that depends on camera position. And in addition to those shiny objects, you want a world around it with lots of details. And it should have a generic renderer, that works well with any scene you throw at it. Automatically culling lots of unseen geometry. And of course AI and physics.
There's simply a lot of things you can strip off when doing a demo. And you can in turn add stuff that increase the "hectic" feeling, but in a way that makes no sense in a game. (Fast flashing of objects, fullscreen fast scrolling textures.)
This probably sounded like I'm not impressed by the demoscene. That's wrong. I think it's very cool, and those in it realy master their art. But it follows different rules that a real-world-like game.