Not the Worst Tarzan movie...

But, then, there are so many awful Tarzan movies. This one retreads the 1932 screenplay and adds little new to it -- elephant graveyard, "Great Escarpment", even the "pygmies"...

And there is copious stock footage, some of it well incorporated but much of it utterly dire. Believe it or not, black and white footage of Tarzan swinging through the trees is inserted before we see Denny Miller swinging in a nice but obviously stage-bound treetop set--and this is done several times, most egregiously in a daylight scene where the switch from color to b&w and back is most obvious. There is a halfway decent Zebra stampede which includes shots of ordinary horses (presumably from some western) overrunning the camera

Acting is not awful, cinematography is usually sound (bar the jarring stock shots), editing is occasionally awkward. Overall, the film could be a lot worse, but that's the best I can say for it.