In a sense you could classify the film as a horror. Schwarzenegger get's a lot of flack for his acting but his zero emotion as a literal killing machine as we witness the police station massacre is a more memorable moment than anything from the sequel. Even the stop motion and animatronics still have a believability, just to how much atmosphere the setting and cast have put into the stakes of saving humanity.
Impressive futuristic landscape kick-start this low-budget action movie that never lets go. It is also dirtier, darker and more depressing compared to the later overblown sequels. One of the reasons why the original is great was that Schwarzenegger played the villain - a cold gazed assassin cyborg out to change the past so that the robots can destroy humanity. Old story in new wrapping perhaps - but it is a good one.
"The Terminator" is for all intents or purposes a B cult movie, even though it lack the cheesyness of a cult movie or the polish of an Hollywood blockbuster, but it still managed to dish out fantastic effects. I never expected this but i believe that Tarkovsky's view on this movie is flawed. Sure penicillin and all that but this movie didn't intent in advancing cinema as art more than it does showing Linda's tits.
The film boasted a number of technological feats, ahead of its time. Also a great (great) platform for Arnold; little talking and more reliant on a physical presence (something he knows well). Story can jump back and forth a few times in an almost confusing manner, but all around a good film.