There are a few movies that show people with their arms, legs and hands cut off, the camera angle hasn't even changed angle, and a large spurt of blood comes pouring out of the amputated limb and amputation site, until the person stops moving and is declared dead.
Also other parts of the body such as the head being cut clean off, blood pouring out. Legs being cut off in plain sight and is gushing with blood.
How is this all filmed and what how do they film it?
As with magic tricks, it's simple once you know how. It's all in the preparation.
Want to cut off someone's arm? Make a tunic (or whatever) that's big enough to hide the arm. Strap down the arm. Put on the tunic. Strap on a fake arm with a quick release and a blood packet. Swing the sword, someone offscreen yanks at the arm, blood goes everywhere.
Hands, feet, legs, similar technique. Add a pump to spray fake blood from the "stump" for extra gore.
Nowadays, of course, it's usually CGI.
Until recently, they would hire an actor who was missing that limb already, and cut off a prosthetic limb. Obviously, that technique didn't work as well with a head. If they need to show a head being removed or destroyed, it would be a trick shot: the footage of a headful actor being spliced into footage of a dummy at the last second.
Watch this for a brilliant example (actual head-splosion occurs at 1:30, but watch the whole thing for maximum effect).
