Double the opening tool, double the opening speed! We've done so many of these we figure we gotta step our game up a bit.
The display cable is now slightly wider to support all those extras pixels. 16.4 mm over the 12.4 mm of the non-Retina 21.5".
We also note a new rubber bumper stuck to the fan's top screw—likely to provide a little extra support for all those heavy new pixels.