Half-Life: Dreamcast is a PC port of the unreleased Sega Dreamcast console version of Half-Life.
A couple of minor bugs jeopardized my gameplay, as I listed in the commentaries, such as the tram not moving in the intro when the rail connects or a scientist not getting properly pushed inside a vent when he is hanging there, but the sounds still play.
Well this is a good PC port, but if you're expecting a significant difference between this and the retail/steam half-life, you might be dissapointed.
In my opinion, the original models and textures are fine, and these new ones aren't really better.
However if you are just curious as to how the dreamcast version looks like, this is as good as half-life and is relatively bug-free.