Ideally, if you're going to design a game for a minimum spec system, you set those minimum specs and work from that. However, there is only so much that can be done with a GeForce2 MX, and that peak was reached about a year and a half ago. Halo is just as valid as HL2 in this argument because it's minimum specs were supposedly fairly low. Using the same argument you're arguing now. As has been pointed out, they weren't actually that low and people trying to run it on an older PC got some unpleasant results (I would know). However, because HL2 is supposed to be DX9 native, and because it is designed to take advantages of optimizations for DX9 on high-performance cards, expecting it to play crisp and clean on an old comp is not realistic. On the other hand, the original HL was designed on a lower end and as such had lower system speed and memory requirements to run at its best. It still runs smoothly on faster machines, of course; there's nothing changed that would slow it down. But you won't see the same transition on HL2 going the other way, no matter what Valve says or what that illegitimate beta seems to prove.
