That was pretty graphic for the state of the technology back then. I was in my early teens when I saw it--rather disturbing to me then. But then again I saw Jaws II when I was even younger and had nightmares for months after.
There was another "horror" movie I saw back then (yeah, so I was under 17...blame the theater for letting my buddies and I go in!) Can't remember much about it, other than the "cute teen girl" was really a teen guy, and he/she killed pretty much everyone at the summer camp.
That messed with my mind for a long time too!
Actually I was about 9 or 10 when I made the mistake of seeing a couple of films .... RABIES and PIRANHA.
Rabies just gave me nightmares; Piranha kept me out of lakes for a good long while.