They tried to explain how they set their camera in this reddit post. Basically what they said was :
so the walls are tilted 45 degrees toward the camera, and the floors are tilted 45 degrees away from the camera, meaning that each should experience sqrt(2) distortion because of the additional length along the z-axis. However, the vertical (y-axis) floor length shouldn't be perceptually changed.
The camera is not tilted at all.
Camera: 0 degree tilt.
Walls: +45 degrees tilt.
Floor: -45 degrees tilt.
My question is : What do they mean by "However, the vertical (y-axis) floor length shouldn't be perceptually changed". If I tilt the walls and floors by 45 degrees and -45 degrees as said, the sqrt(2) distorted walls (the walls have Z depth and are perpendicular to the ground) line up nicely, but the ground gets distorted (obviously). So I distort the ground tiles by sqrt(2) but this essentially stretches the ground by 40% so every vertical movement now has to be increased by 40%.
Can somebody explain what's going on? Any help would be highly appreciated.