Nice illusory balls! :) Somehow rotation does not work for me correctly in the Web version, it is constantly rotating, unless I set the rotation speed to 0 (but then I cannot rotate).
Please do not call it non-Euclidean though... non-Euclidean geometry is a completely different thing, portals change the topology, but the geometry remains Euclidean. Non-Euclidean geometry is so strange and cool that gamers will not even notice the strangeness (but they will still notice it is cool). Unfortunately some gamers recently have started confusing people by calling portals non-Euclidean :(