Hi all,
This might all seem a little irrelevant but please bear with me.
To get straight to the point, Special Stages from Sonic the Hedgehog 3 may look spherical but are actually flat.
A video of a special stage in action:
It looks spherical (I will get to this later) but cannot be. The floor has a squares pattern which is consistent throughout, and you would be unable to fill a sphere with perfect squares, the squares should narrow and meet at a single point as you get to one of the poles of these worlds, as you see with the longitude lines of the spherical Earth model. Furthermore, the stages are set in perpetual daylight (or night time depending on the stage), with no change in light levels as Sonic travels to the other side. If these worlds were round, the light source would only hit one side of the world.
As for looking round, I think there are a couple of things at play here. Firstly, this game would have been mostly played on a CRT screen considering it was released in 1994. These screens have a curve which I believe warps the perception of the viewer to see more curvature. Also, If we say for instance that Sonic can see for 300 pixel lengths in all directions, this would draw a circle of viewing field with him in the centre, I think the curve of this circle is what we are seeing on this world.
Yes this is a video game with a fictional "globe" of collecting blue spheres (which I have no argument against are in fact spherical, they can be readily observed as such), but I think some of the observations can have meaning for the real world as well, because games are still bound by the laws of mathematics. Here we see a world which absolutely must be flat and yet we see a curve on the horizon which I believe can be explained.
I don't really intend to get into the real world counterparts, I posted this to see other peoples thoughts, but this shows that observations might not always match what maths dictates and a similar thing may be happening here on Earth?