I thought it was bad. See red for answers to your questions...
In Sci-Fi, the most important aspects of a movie or book is one of two things, the "creature", or the "setting". Here, though, the planet isn't even named but in a very quick map scene, and the only bits of it we see are the valley where they are. For all intents and purposes, it is essentially a primordiol world, minus almost all of the life. He may as well have set the movie on an inactive volcano in iceland. In addition, the audience never really knows what alien thing is going to happen next, and can't relate to any of it. It's like Ridley Scott saw "Evolution" (The goofy one with David Duchovny) and said to himself, "I bet we could make that into a serious movie. Everytime we need some dramatic event, I'll just toss in whatever neat alien prototype I can think up, and we'll make it look cool post production".
In this movie, Scott tried to tell this grand, sweeping story about origins, and there were several nuanced plot points that were given such short shrift that I in the audience didn't really connect with them. (Example: Humans search the cosmos for their creators, viewed partilly through the eyes of one of their creations.) This really could have been given a 2 or 3 movie treatment.
Whats unfortunate is that, lost in the bad reviews are some VERY intense and excellent performances by Noomi Rapace and Michael Fassbender. Fassbender, I thought, did an AMAZING job pulling off something that was designed by humans to be as human as possible, but was just a bit...off. Rapace is believable throughout the movie, and given what she goes through, that is a high compliment.
I would give it 2.5 out of 5 stars.