Many of the scenes in the video look like they are moving with the composited character moving fluidly in the scene. Take this scene for example:

The camera pans out while the Undead happily gobbles away on his victim. These are some the easiest to pull off because the background is actually a still image with the composited undead being the only thing that is really animated. Then, you just start with the scene zoomed in with the editor and slowly pan out to regular size. Again, notice the shading on the Undead. I created a single point of light in WoWModelViewer that was about eight feet about him and a about a foot in front so that the shading on his body would look like it was caused by the light in the scene. The scan lines give the impression of viewing the scene through a multiplexed indoor security camera. All scenes of indoor cannibalism are done like this to give the impression like Day of the Dead where everywhere they looked there was a zombie eating someone.

This next scene takes the panned static image one step further.

I had to use a few tricks in Vegas to make this scene work correctly. First of all, it is a Succubus (a warlock pet in WoW) walking on the side of a wall. But since the wall is set in perspective I had to make her look like she was walking toward the camera. I did this by changing her scale at the beginning and end of the scene. It took some futzing to get the starting and ending scale to look correct.

Second, she had to walk, and not just upright but on the side of a building. Since WoW Model Viewer doesn't let you turn the models on their side, I used Vegas again to rotate her 90 degrees counter-clockwise. One thing that has always bothered me was animated characters walking but their steps being out of sync with their movement speed. This would result in their feet either sliding forward as the walked or sliding backwards like they were on ice. I adjusted the playback speed of her walking until it matched the distance traveled. To get it right I would watch where her foot (or hoof, as the case may be) would land and make sure that it stayed there until she lifted it to take a step forward.

Finally, once all of that was done I had to make it look like she was stepping into the light generated by the light fixture on the side of the building. I did this by changing her brightness levels as the beginning of the scene to a very low setting and then gradually increasing it to full brightness by the end of the scene.

Add some panning of the static image and you have a very complex scene that looks like there really could be a hellspawn walking on the side of the building.