I'll make it for you. However, like I said before, there are things handled by the engine. I can put things in a script, but there is the possibility for errors. For example, I can script it so that if the player is holding the new weapon and kills Metzger, then the new animation will play. However, what if the new gun is in the right hand, but you actually kill Metzger with the Ripper in your left hand? In this case, the new animation would still play, even though it might not make any sense. I have given this some thought. I can't think of any way to avoid this problem during combat. However, to script it as something that would occur right after dialog closes would be alright. For example, once Metzger's hit points get very low, he initiates dialog. From there, you can let him go or choose from a number of ways to kill him based on the weapons you are holding. So, if you are holding a molotov cocktail or flamethrower, that new burning animation could play. If you are holding a special gun, then the exploding head could play.
(If there is someone out there who can translate this to German I would appreciate it.)