Perhaps a reference video would be needed to show this, but to clarify, merely the portal and its animations appear nearly impossible to create, the frame itself is simple diffusion and optional reflection. Mind this is using cycles.
I though the best way to attain this would be to have the position of the camera changing cause a movement of the portal textures however it has proven futile.
And so I ask, is this possible in Cycles?
My original plan was to use the UV Warp modifier to create the movement effect, with several planes underneath each other to create the depth. However, the way it appears to be a void, another area is the piece I lack.
The frame of the portal, again, is not a problem.
In reference to a comment that referenced a similar concept using a Nether portal that showed the Nether upon the other side, is similar, however there is no need to create another world on the other side, as I want to stay true to the visual mechanics of Minecraft.
Here is an example of the in-game version of what the goal is. https://youtu.be/ZpJiEbgo3Z4