No blood is shown unless your watching the collectors edition
Some of the more violent scenes sort of have tamed down, and appear comical onscreen by today's standards, but back in 1971, they were deathly serious. It's still a hard R movie.
If you watch the movie on Disney+, there is a fair amount of bloody violence.
Bloody shootings and injuries shown but nothing graphic.
In the directors cut A character is shot twice in the chest with a shotgun. Tiny elements of blood are seen, not graphic.
In the directors cut A man is shot in the face. We see blood briefly splatter from his head, not graphic.
A fleeing man is shot in the back, (A non-bloody gunshot wound is shown) falls down a set of stairs and presumably dies.
A woman is shot by a sniper. No blood.
A man is shot several times from a distance; we later see his blood-covered body.
In the directors cut There are two other shootings along with a head injury from broken glass.
A man slashes at another man's arm with a knife and injures him.
In the original it is just offscreen and in the directors cut A man is kicked and beaten by a pair of cops briefly. (We see his bloodied face later.)
In the directors cut An accident scene shows three very bloody corpses. Graphic but brief.