Anyone with experience in 3d modeling should be able to use this tool to view the game's models and animations.
Modifying the game's UI is also possible by editing the gui0.pak file. That file is broken down into all of its parts in the "gui" folder. All of the gui files can be viewed with a text editor.
All of the 2D animations are done in flash, and then
converted into .gfx and .tga files.
flash.pak is one of the few files that has additional data in the localized version, so if you want to look through it make sure to unpack both.
.gfx files can be converted back into .swf files quite easily, but the links to the .tga files are broken. Any of the images you see above won't appear if you run the .swf file.
If you have flash, you can manually paste the .tga files back in and watch the animation. I'm not sure if there's a better way to do this.