I have a very odd and vivid recolection of the first time I saw ALIENS with friends at the flicks - we sat really close to the front, and my abiding memory is that the whole movie was like watching a tennis match for me: as in, my head was constantly whipping from one side of the screen to the other!! I think this is obviously because we were "front-row'ing" it, but it's also a mark of how incredible Cameron's use of screen-space and action are. Not to mention audience involvement!!
As I said before though, I don't even really consider the second film to be primarily Science Fiction - it's an action movie, one of the very best, and doesn't have nearly the (a-herm) "mythic resonance" of the first movie. I mean, full-grown Xenomorphs in the second film are really just relegated to moving targets for the most part! (No diss intended at all though).
Speaking of (a-herm) "mythic resonance", this is now, in retrospect of Ridley Scott's career, something he is very consciously aware of in his SF films. And for all it's niggling problems (ie A space mission put together by the most incompetent HR department in the history of space flight!) Prometheus is also stuffed full of those resonances too, which I loved
