Although I don’t have high hopes that they will take it (I’m kinda late 
) here it is:
http://www.youtube.com/watch?v=0CA5CPHRXDc
This took veeery long, also due to the weapon 3D model but in the end I like it. 
I’m also thinking of using picture files for some parts to speed up the work and lower the rendering time. With that I would have been done sooner with especially the background. 
Used Synfig for 2D animation (duh), Cinema 4D for weapon, After Effects for muzzle flash and smoke and pencil for the destruction of the desk. If you want to know how I did a certain thing, just ask. 