Well for the first one (Craig in Goldeneye) it was actually a matter of going into Adobe Flash (I know, most definitely not designed for this, but worked quite well) and importing the Goldeneye gunbarrel (Ripped from the UE DVD), then importing the QOS gunbarrel (Ripped from the QOS DVD) behind it. From there, I masked Pierce Brosnan out in the shape of a circle, so we can see Daniel Craig behind instead. From there, obviously the blood won't show up on Craig, so I shape tweened that myself. I also had to make a number of small adjustments to fix timing, make sure none of DC's gunbarrel was visible etc.
For the Bond 23 Concept, I simply made my own dots at the start, which move a lot slower than they do in QOS. Then I imported the QOS gunbarrel and let that play out until Daniel Craig fires his gun, at which point I paused it. I then added in my own blood with another shape tween. The effect I used is 'multiply' so you can see through the blood and it gives everything the red look.
Now, I'm quite sure there are better ways of going about this. I think Adobe After Effects would be a wiser choice, but since I don't have it (I'm actually picking it up in a few days), I work with what I have. Thanks for asking. Hope this answers your question. If I haven't explained it clearly or haven't answered it, feel free to let me know.