Not so bad as some had pointed out.

Rating: 6/10 (14 June 2017)

First off, I would like to say that if you are someone who writes a review based on your emotional experience throughout a film or uses another movie as an anchor point for comparison and ratings, then I do not find such ratings reliable.
I won't be comparing this to other sci-fi movies as they are each on their own. But lets get started.
This movie kept me at the edge of my seat throughout, partly because I was expecting such experiences for a horror/thriller genre. I certainly found this movie enjoyable overall, with the right amount of tension, suspense and a few memorable scenes. There were some jump scares but none so sudden to the extent that they would fling you off your seat. The setting was believable, along with the 'tools available' in such settings (no guns or lasers).
However, if there is one thing coming from other reviewers that I do agree with it would be the unprofessional-ism of the astronauts and the slightly unrealistic life form itself. Though it could be argued that being a more advanced life form comes with increased resilience to deprivation of life supports.
It would also be perfectly natural for trained professionals to act in an emotional and irrational way (perhaps not as easy as portrayed in the movie) when in a never before seen predicament.
All in all a 6/10, it is decent and worth a watch if you go in with an open mind instead of looking for realism or comparing it to Alien. Would have been a bit better if the characters and the life form were a bit more believable.