Screen comparison 1:
The bird's feathers in the back are rounded in the second pic, while in the first they are more pointed due to less polygons on the bird. Also on the tree branch, there is almost no shadows in the first pic, while in the second pic they are many of them.
Screen comparison 2:
Again in the second picture from the show floor playable demo, the tree has many more shadows then original presentation video. The bird's back has more textures giving it a more realistic look as well.
Screen comparison 3:
The first picture shows a large rock next to the tree trunk, but in the second that rock is gone with plants replacing it. The bird's wings in the second picture again highlight more polygons and thicker textures than the first pic's more ridged flat look.
Screen comparison 4:
Look at the flower in the bird's beak in both pictures. The flower is fully textured on bump mapped even with the Pistils showing in the middle. Compared with the flat shaded flower in the first picture from the presentation video, you can see a big difference between the two. The bird's belly in the second picture also has some form of HDR lighting and fur shading textures to give a more real look than the bird in the first picture.
Screen comparison 5:
The bird in the second picture actually has light reflection off it's eyeball, while the bird in the first picture has more of a flat lighting on it's body in comparison.
Starting from the top down, we have 5 sets of screen shots from the Japanese Garden Demo for the Wii U. In each set, the first picture is from Nintendo's E3 presentation demo video when Reggie told the audience that this was an "early sample of what the system can do". The second picture in each set are from the Garden tech demo that was playable in real-time on the show floor.
Reggie had said in an interview that the Garden tech demo presentation was made with early dev kit hardware and was just a small example of what was coming. The show floor demo was improved quite a lot in comparison. Improved polygons, bump mapping and textures on the bird, followed with overall lighting and shadows improvements were added to the playable tech demo. It's really nice seeing Nintendo go the extra mile on a lot of these details that could otherwise be easily missed. The power debate for the Wii U has been ongoing in most the Nintendo forums, but the fact remains that the dev kits are still not finalized yet and improvements are still being made.
This real-time demo has to be a good indicator as to what to expect graphically from the Wii U, but I'm willing to bet that full games made from the ground up on the system will end up looking better than this in the long run. The report that some developers have been able to port full 360/PS3 games looking exactly same in mere weeks to the console is a good indicator of it's power I'd say. Nintendo is not one to show off graphics unless they actually have something to show and are proud of it. This demo to go along with Zelda are amazing examples of what the future could hold graphically in our games to come.