I read some of those 1979 alien reviews. I love how harsh they are and these days every review is positive!
It's constantly compared to Jaws and Star Wars and clearly viewed to be inferior.
To be fair those reviews aren't even unfair, just think about those when you're about to hate Covenant even Alien wasn't seen as an original film back in it's day...
I also like how blockbuster summer films already got mocked in the seventies
Times aren't a changing Bob Dylan!