Tempest is indeed a terrible example:

- it's a static perspective view, less complex than sprite based 2D

- it's implemented on a vector screen, where the cathode ray gun is drawing the lines instead of the software, not a bitmapped one

- almost everything can be precalculated and only vertex locations need be stored

Of course it's still a creative game, but not very hard to implement.

It should be noted that Battlezone wasn't actual 3D since everything happened on a fixed plane, but it had dynamic rotating shapes and the like so much more advanced.