Alien and the many plot holes

    "In Space no one can here you scream"

     Alien is an amazing sci-fi horror, it succeeds in creating a tense atmosphere that superbly conveys dread and fear of an unknown, unseen evil entity. While I was watching Alien I noticed that the film had some plot holes. For example, The Alien is shown as having intelligence equivalent to that of a human being. Unfortunately that doesn't explain how it is able to navigate around an alien (to it) spaceship on the first day of its existence. Or conceal itself while doing this. Not a big plot hole but maybe this one will be more of interest. With apparently nothing to eat, the face hugger transforms into a 500lb+ full grown alien in less than 24 hours. How and why this occurs is not only handwaved by the film, it barely seems to amaze the crew of the Nostromo who die trying to fight it. Spacecraft require an oxygen-rich environment. Using flamethrowers to hunt an alien in such an environment is the equivalent of pouring gasoline on oneself and then lighting a cigarette. The film completely handwaves this and several times flamethrowers are used in situation which would have incinerated the Alien AND the crewmember using the flamethrower. 

     At around 20 mins in when the members of the Nostromo are exiting the ship to leave to explore the Alien ship, the wind is blowing at high speeds, yet when the steam is shown from the lift it is just drifting down rather than being blown away at high speed. In later scenes it shows the high wind blowing. Another scene in which Ripley tells Lambert that life raft will only hold three when there are four crew members remaining (out of the original seven). Since the early part of the 20th century having enough lifeboats for crew members and passengers has been the law. It is exceptionally unlikely that spacefaring crews would sign up for a mission knowing that in an emergency at least some of them would have to be sacrificed or sacrifice themselves because there weren't enough lifeboats. I didn't notice most of these goofs until I viewed the movie multiple times, I was shocked at the amount of goofs I found during my rewatches.