The final shot is of the head pleading "Bury me! Bury me!", over and over. It still gets to me.
It's the cruel fate of this innocent girl that makes this movie compelling. She's prettier than the Mad Doctor's niece, at least before she's turned into a fucked-up science project through sheer randomness. If you grew up watching cheesy horror movies, you know that means she's supposed to be the one who gets away and marries the handsome young scientist, and the thwarting of that expectation is unsettling. Also, the handsome young scientist is a bit of an amoral bastard.