I looked up what "the sentinel" was, and it turns out it was a game in 1986, that works on the BBC Micro and Commodore 64, and has 3D graphics! I didnt even know it was possible to do that on average computers in 1986!
There was no texture mapping, and the 'trick' that makes it work is that all you can do is rotate/pan in place. The only movement is instantaneous teleportation.
The world procedural generation from a seed alone is amazingly well implemented in an environment so constrained most programmers nowadays wouldn't even be able to do anything in.