Well to be fair there is a way of configuring it to use one core, but it's not fail safe. Rob over at Ultra Hal seems to have fixed it to work okay with his UltraHal, but plans are afoot there to move over to an Ogre based avatar.
The thing is though, it's hard enough to get people to download the Haptek PLayer but then to expect them to run the hack too....well unlikely for the regular user. I was into Haptek in the past and even I can't be bothered with it.
But yes I agree it was good at the time, there have been rumours for a long time that they were working on an upgrade, but with no official news since 2005 I will let you draw your own conclusions. I don't think they are interested in web stuff any more.