Great engine!! Great multiplayer code!!... Game? What game???
Quake was a technological wonder, after Doom id really had a hard act to follow technology-wise, yet they once again proved their programming prowess with Quake = the first fps with a true 3D engine.
And what an engine it was! After years of being stuck on the world of 2.5D games, Quake finally delivered true polygonal bliss. The end result was pretty much obvious: better sense of space and depth, smoother animation, use of effects like the portal or the cool underwater-distortion one, etc. etc. Quake also applied it's 3D-ness to such things as the player's Pov, which swayed and leaned around quite realistically. A feat that really made the game feel a lot different from the now static-looking 2.5D fpss; ditto the character models, which moved way smoother than sprites, and also came with the added bonus of being able to explode in little chunks of red meat, yes boys and girls, "gibs" were born with Quake.
The multiplayer area is also the other point were Quake broke the mold. As everyone knows by now, the game replaced all the hassle of multiplayer net-play with the now common server-client architecture, which was not only much more intuituive, but also much more reliable and fast, especially when you consider the setup prep-work that was usually involved with multiplayer gaming.
Also, being a metal fan I really enjoyed NIN's contribution to the game's soundtrack, tough it seems to be too depressing/experimental to most players for some reason. Still, if you don't like it, you can always pop in your own audio cd and let 'er rip while you get it on.
What "didn't" I like about the game?? Well, there's no game to speak of!! :)). Seriously, Quake would begin id's trend of just forgetting about game design and instead providing the best technological wonders they could come up with. This is especially evidenced by the open architecture of Quake. It's set-up so you can customize it to your liking, ad mods to it, ad skins, textures, levels, sounds, etc etc. Heck, they even released the source code!
Id just figured "Why the hell bother designing the game when we just can release the technology?" It may be a reprehensible idea, but it's smart! Think about it, Quake off the box was a piece of shit. The game itself has even less story than Doom (and you thought that wasn't possible!!), the weapons are copies of Doom's (save for the Axe and the Lightning-throwing thingie) with new yet crappy 3D models (the rocket launcher is just a brown rod!!), the level of interaction was toned down to near-retarded levels with the removal of the use key in favor of a jump key, essentially trading off the ability to use things for the world's crappiest jump (primary reason for the discovery of the rocket-jump) result? You activate gigantic buttons by bumping into them... groan....
But wait! That's not all! The levels are dull techo-goth places with a heavy dose of the brown color (hmmm, crap comes to mind in more ways than one!!), populated by stupid traps (??WTF??) and seemingly randomly-placed enemies, which to be fair are the only cool things that come with the game. The single player campaign is a joke, with the only good moment being the fight against Chthon at the end of episode 1 and the initial joy of watching everything in 3D and all the Lovecraftian imagery. The multiplayer part saves the game, but then again the maps that came with the game were sorely lacking in just about every level.
The Bottom Line
Quake sold Gazillions of copies!!! Why? Because it didn't matter whether it was good or not off the box!! You bought the game, and then turned it into whatever you wanted! And I'm not just talking about the level add-ons and stuff like that, I'm talking about serious reworkings, like Quake Rally and the like.
Quake is sort of like a piece of real estate, get it? It's what you put in there that eventually turns the game a worthy experience. It's a piece of remarkably well made technology, with enough of an open architecture to satisfy most pseudo-designers (though it would still require a high level of proficiency to do stuff like "real" level editing). That's what you pay, and that's what you get. Not a game, but a 3D-enginered, multiplayer-capable, piece of clay. This is good, REAL good. On the other hand it's pretty shameless in the sense that the developers simply washed their hands of most, if not all, creative content... hmm. That's bad, real bad...
In the end you'll have to ask yourself what do you really want. Back on those days Quake meant 3D and multiplayer. If you wanted that, you went for that. If you wanted say... good fps gameplay, you went for Duke3D (or even Quake add-ons like Scourge of Armaggon) and the like. You had to think before you bought. Of course, nowadays it's just completely stupid to play Quake. No reason to bother with old technology when you can have the new and upgraded version: Quake 3 Arena, even less of a game than this one, and destined to the same oblivion as soon as Quake 4, 5, 6, etc. get released.