I consider Terminator (1984) to be scifi horror, with a strong leaning to slasher style (more bullets), save that the victims aren't too stupid to live (sure a lot died, but I wouldn't call it due to mind boggling stupidity). To me, the first and second movies are the only ones I'll rewatch (2nd one is scifi action rather than horror), and I saw the first one not too long ago and it amazes me how emotional it can still make me, including just how nightmarish it feels at times despite having seen it about 20 times (in about 20 years).