tfishell: I had 3Dfx running pretty well for the first few gameplays, then it started freezing as soon as I loaded a save game. So I switched to software rendering and while it certainly isn't as pretty, it still runs well. :)
At least for me Direct3D seems to run fine in all my PCs where I've tried it, as long as I installed the 333b update. Without it, only software rendering would work (and maybe 3Dfx with nGlide). But it still has the movie playing bug for me on anything newer than Win98SE (I'd like to see GOG fix that, albeit the movies are not that great in quality. But they contain a big part of the story between missions, being many times like 10 minutes in length).
And I agree the music is pretty nice in places, but still a bit... shallow. Like some good elevator music. :)
As for the rest of the game (so far, now in mission 7 I think ("The Ways/Blight"), playing with the hardest difficulty):
+ It is a bit different kind of FPS, as most of your weapons are actually spells, like slowly moving homing spells that eat enemies health over time as long as it hits them, or area damage spells like the earth quake spell (tremor?). And as at least I keep running out of spells all the time, I kinda have to try different spells to survive.
+ I guess the graphics are quite ok for a 1999 FPS game, but certainly they have aged.
+ Some levels are pretty atmospheric (I liked "The Wind" that you have to run away from in The Ways level, quite creepy and haunting).
+ There's some nice variation with the gameplay levels, e.g. one level where there are only traps, no enemies at all.
- But still, overall I haven't been overly crazy about the gameplay at any point. It's ok, but nothing more. You can see the age in the gameplay for example how the enemy monsters just stand forever on their spot, until they notice you or you attack them, at which point they start wake up and start attacking you. The same as in Wolf3D or Doom already. As far as I can tell, the enemies don't patrol or do any other things one might be expecting them to do. They mostly just stand there in one spot doing nothing.
- What's up with that training mission where you have to set up traps for the invading monsters, a bit like a first person view tower defense game? I think I am already past 60% of the game, and I haven't seen that same gameplay mode in any other levels besides the training level. Or is it only for multiplayer sessions?
- In a couple of levels you have fellow NPCs that fight along with you, but they seem pretty useless. They just run around like headless chickens, maybe are able to kill an enemy or two if they are lucky, and then die away. So you'll play rest of the level alone anyway. Nothing like the friendly NPCs in e.g. Half-life which were actually useful, and you could even use to your advantage for ambushing enemies etc.
So considering this game came out one year after Half-life, I feel it is eclipsed by it quite a bit, even if it is quite different FPS.