I think you're right, and while I think something simple like fading in and out the elements based on distance would be reasonable (since the game would be unpl

I think you're right, and while I think something simple like fading in and out the elements based on distance would be reasonable (since the game would be unplayable otherwise, as you'd be able to see the entire level), the choice they appear to have made (something non-orthographic) seems to essentially be fully encoding the extra dimension. Otherwise, I can't see how the goomba would appear to get bigger as it gets closer to mario.