Hey, Mario 64 isn't "real 3d". It is just a projection of 3d coordinates to 2d triangles on a 2d screen.
IMO It depends on how you view it. You can render the game stereoscopically and see a different view in each eye... then I would call that "real 3d".
That’s exactly what the Virtual Boy does.
If you could perceive real 3D, you would be able to "see" completely everything in a scene, including the back of objects, or objects behind other opaque objects.