I saw Halloween first when i was a kid and at that time i think the only ones that existed were 1,2 and 3.
I wasn't aware of any of the sequels at the time, so saw it unknowing of the weight of the franchise.
The film blew me a way and being a kid it was one of the only films that ever really scared me and freaked me out.
In your list of scenes you left out the final moments where the camera shows us various empty shots in the house etc, suggesting that he could be lurking anywhere. I think that is what really sent me over the edge as a kid.
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MIKE: I've got it! Peter Cushing! We've got to drive a stake through his heart!
VYVYAN: Great! I'll get the car!
NEIL: I'll get a cushion.