With the video compositing, I selected the frames I needed, then composited them into the scene, often manipulating the frames.  I then animated on top of that.

Click on each image to view the animation.  (Quicktime format)
(3.48MB)
 
Here Drew (Christopher Lloyd) and his sidekick, Flux are escaping from the evil robot who is shooting electrictiy out his finger at them.
(1.52MB)
 
In this animation, Drew is wearing a fly suit to climb up and down the air vent.  We had to get the fly suit off of him for the rest of the gameplay.
(2.14MB)
 
Drew carries a bottomless bag in his coat which holds all of his cartoon inventory.
(4.52MB)

Drew uses the Pump-O-Tron to gain strength.  This is just a clip of a larger animation.
(1.03 MB)

Drew uses objects in his inventory to slide into the next scene.  I think the actual footage of him was just jumping off a chair.  I had to do quite a bit of manipulation to get this to work.
(507 KB)

After Drew talks to the sheriff (on the porch-not in the scene here) he heads off for a show-down with the evil-cowboy.  I added in the hat and gun holster.  It was sometimes difficult to get the video to match the skewed perspectives of the background art, so I would have to place each frame individually.
(1.52 MB)