To achieve the retro video game look, I wanted it to look like the opening and closing parts of the film were being watched on an old cathode ray television.  To achieve this, I added scan lines, separated the RGB values a little bit and added a warp. The backgrounds were already designed in 4:3 aspect ratio for this portion of the film.  I also played around with the brightness.

For the portal, some glows and echos were added to compliment the pixel FX that were already in the animation.  The sheep’s world was in glorious HD so the only FX that were needed were the previously mentioned FX, which Max retained even in Sheepland.