In some countries prostitution is illegal - I think that should include graphics whores!

I think you're kinda confusing the dates here. I mean, in 1996 we already had Quake and Tomb Raider, in 1997 we got Quake 2 and Jedi Knight, in 1998 we got Half-Life and Unreal, 1999 was the year of Unreal Tournament Quake 3 and lots of other notable 3D games. The truth is that by 1998 those "fake 3D" engines such as the Build Engine were already considered dated and "real 3D" engines were the standard. And I don't see how the games and technologies of the Quake/Half-Life/Unreal generation were less 3D than the ones we got in 2004.

You said the word: immersion. Graphs help, but... Again as mentioned, I prefer GTA Vice City than GTA IV (no nostalgia here).

I was talking application, not technology.

the tech was there long before people started using it (Ultima Underworld had a fully three dimensional environment long before ID popped out Quake) but virtually no one was designing on a three dimensional level until Doom 3 showed people how much lighting effected the game world and Half-Life 2 showed people how much vertical (as in multilayered) environments expanded gameplay.

prior to that most everything released was still being designed with everything existing on a single surface; the surface may have been a bit wavy and some of them managed to get a bit wide in addition to being long, but few actually managed to go for long, wide, and deep.

the games you mentioned were notable exceptions to the norm (I argue about tomb raider's inclusion though, most of it's environments were built on a single surface instead of having one environment stacked on top of another environment, Homeworld would be a better inclusion IMO for it's application of space battles not happening on a flat surface) while most everything else was just two dimensional designs built with polygons.

You are the first person I know who credits Half-Life 2 for such a thing. And really, I've played zillions of shooters in my gaming career including many obscure ones and nothing I have observed hints at what you are describing. In fact I don't recall Half-Life 2 as being a game that makes a notable use of vertical environments. I remember Jedi Knight for having overly complicated three-dimensional level structures including jump puzzles, I recall massive use of all three dimensions in the UT and Quake 3 era of deathmatch gaming (not to mention games like Descent and Forsaken where you don't even know where up or down is) but really, I don't see how HL2 has set any new standards in this aspect.

Edit: Now I even googled for some source that will support your claim about HL2 but really, all I find are usermade maps that make an absurdly massive use of vertical level designs.

Hm... risking to sound like a retro-bore PC gamer, which I possibly am, I have to agree with the above in stating that I still think that nothing has surpassed Baldur's Gate II in overall gaming experience, and this game was released in 2000! Which is more than a little sad. :-(

The greatness of that game is in story telling, but...

I even find that the Infinity Engine isometric view looks fine enough to my eye, and is from story telling perspective preferable to the frantic camera angle of the mouse point and click console import.

think about the parts where you have to fight through an apartment building, the use of multiple floors and tight compartments .... I hate Steam un-remittingly, and Max Payne did all of that much better, but Half-Life 2 was when people started paying attention and that is what I'm talking about so I give the credit to Valve begrudgingly.

I'm not writing a term paper and I don't have any sources, I'm talking from what I experienced as being a avid gamer for nearly 25 of my 32 years of life.

THE GAMING INDUSTRY DID NOT START WIDELY DESIGNING ON AN ACTUAL THREE DIMENSIONAL LEVEL UNTIL ABOUT 2004.

prior to that most everything was designed on a single surface, polygon resources were used to sort of crumple it up a bit, but few games from before then couldn't have been built with 2D elements. Jedi Knight did have some highly complex environments, but most of it had you walking along a linear path of room A to room B, and nothing nearly as complex as the first Quake. I think you still hung up on the idea of 2D pixel art vs 3D polygon art, I'm talking 3D design vs 2D design and when people actually started using 3D assets to design three dimensional environments.

That's when they gave up, after realizing that fully 3D levels are hard to map on a surface, and controlling units in full 3D is a pain. Have you seen the largest dungeons in M&M6? Duke Nukem 3D? Unreal Tournament?

but Half-Life 2 was when people started paying attention and that is what I'm talking about so I give the credit to Valve begrudgingly.

That is EXACTLY what I think!