Left me feeling confused

Rating: 5/10 (5 December 2018)

-Fist, Jennifer Lawrence's performance was awe-inspiring for a script and a partner she had. One could feel empathy for her even in the very odd movie twists.
Graphics were beautiful, the rest...
Here is what I would have loved seeing:

Bar and barmen are definitely referencing "The Shining", would be awesome if that was a ghost ship with some horror/mystery actions.
The plot going from a love story to her going insane and him going full stocker like in the "Gone Girl" would be excellent too.

What really happened. Super weird guy wakes up a hot girl... They fall in love; they have a fight, they solve a problem, they live together, the end.
Things that bothered me personally the most:

Where did the birds, in the end, come from?
Didn't they use all of the 5300 people's food in the 88 years on the ship?
No children?
Only one medical tube?
No function of automatic crew alert when the ship goes boom?
The ship can fly next to a red giant but can't withhold asteroids?
You don't melt down when you are fired with a nuclear well, fire?
Obviously, no way to go back to sleep?
The guy spends a year on the ship and doesn't wake up other engineers?
An engineer doesn't realize that the ship is malfunctioning for two years even though it glitches all the time?
Why is a journalist richer than an engineer?
Why can't you swim out of water without gravity? There are still dense particles around you.

So many questions... Confused me...