Originally posted by: Triumph
I believe Descent had true 3D, but it may have operated differently than today's engines. The ship had 6 degrees of freedom and the levels/opponents could be "above" you so to speak. Although you had differing levels in Doom, one level couldn't be below another level; you couldn't walk underneath a set of steps. And the map in Descent was a wire diagram that could be rotated freely in any direction.
But the game didn't have mouselook, making it pretty damn hard to navigate with the keyboard when you're rolling and pitching and yawing in every direction while another ship is attacking you. I hated that game.