Battlezone from 1980.
You can see it/try it here:
http://games.atari.com/arcade.php?game=battlezone
This game was the first to generate a "revolutionary 3D" (not S-3D) world for the player.
It's a tank game.

I remember when I first saw this game in 1981, it was an awesome experience for its time. You can't replicate the feeling of having your head in the sights and using the controls with an emulator unfortunately, the sound was very atmospheric too.


From the Mame history file :

Battle Zone went into the arcades in 1980 and created such a sensation that the U.S. army ordered modified versions of the games to use in training.

Battle Zone was the first environmental 3-D landscape game. The game used a system of bit-slice processors called a 'mathbox' to do 3-D calculations for the display. This kind of 'squeezing the most out of minimal hardware' mindset was what led Atari to create the innovative games it did in the 1980's. Approximately 15, 020 units were produced.

As Battle Zone was so innovative for its time, the US Army commissioned Atari to create a version of the game for infantry vehicle training (called "Bradley Trainer"). Ed Rotberg was assigned the project, but was very opposed to it. Major Dave Robinson and General Donn Starry of the U.S. Army were responsible for bringing Atari the idea of making a military version to be used in training.

* The Creation of Battle Zone : The idea of a tank simulator was championed by Morgan Hoff, who became the project leader for Battle Zone, while Ed Rotberg was the principal programmer. Ed Rotberg : "Morgan Hoff more or less championed it and decided to put together a team to implement the game. Given the technology that we had, the real challenge was how to make the game appear as if we had more technology than we did. And the question was always : How do we involve the player? Meeting those needs was where the artistry was involved in designing a game in those days.".
The developers used brilliant software code and innovative circuitry to create a high tech look. But some low-technology tricks were used as well. For example, a simple band of red cellophane was applied to the inside of the Battle Zone screen. Placed across the top of the screen, the result was red colors for the radar and warning messages, even though Battlezone didn't have a two-color display. A game takes on a life of its own, Rotberg said : "Most games rarely turn out exactly the way that you plan them. Every time that you play the game, you try to amplify those things that are fun, and you try to pare away those things that are annoying and really not enjoyable. It is kind of like a story that grows in the telling.".

The volcano erupting in the background was created by Owen Rubin (Major Havoc). Rubin pestered Rotberg to add the volcano but he was too busy to write the code and told Rubin that if he wanted the erupting volcano he'd have to write the code. The next morning, Rotberg walked in to a volcano erupting onscreen and the code listing on his desk.

* Remembrances from the Video Game Masters : On the erupting volcano in the background of Battle Zone, Ed Rotberg said : "One of the other programmers who was working on another project in the same lab kept saying, 'Why don't you make the volcano active?' I had enough to do just to make the game play. And everyday he would say 'You know, you really need to make that volcano active.' He is really currently one of my very best friends, and he is a wonderful guy. But he kept pestering me about this. One day I said, 'You're a programmer. If you want the volcano active, you write the code and I'll put it in.' So I came in the next day and there was this chunk of code on my desk describing the motion of the rocks and such. I took an afternoon off and put the code into the program. That's how the volcano became active. It was never in the design.".