I didn't like the ending

As someone else pointed out, it's fairly standard in sci-fi horror to have a sad ending. (SPOILER ALERT for multiple classic films' endings ahead)

"The Thing": maybe they saved the world, but the protagonists are soon going to freeze to death.

"Invasion of the Body Snatchers": There's even a meme about this one, with Donald Sutherland's freaky face pointing accusatorily, and the woman who hasn't been converted to an alien yet screaming in terror.

And that's not even counting all the classic Twilight Zone episodes that ended on very dark notes.

Now, one thing I would criticize about the ending: what's the likelihood the fisherman would look in, see all those tentacles writhing about, and think "let's get in there!"?

I didn't care for it.
I predicted it.
I thought the scenes in space were stupid.
The pods launched at different times and were going in opposite directions, one to deep space, one to earth.

The pods flying side by side...both toward earth...stupid writing.

Also, the advanced math needed to hit the exact trajectory to reach earth and not burn up....but the monster supposedly just grabs the stick and adjusts course perfectly.

Too stupid to not annoy me.

It isn't "sad," it's a full-on freak out! It's a horror movie. It was doing exactly what a horror movie should do.

It was a bleak, ugly movie. Rebecca Ferguson's rack was a nice distraction, though.

It was the perfect ending for a world where scientists appear to be fully retarded: cripple on a space station? nope.. The second Calvin moved it should have been frozen and studied somewhere where it could be vaporized instantly, either a separate space station or one in the moon. It’s like none of the governments on earth even knew what the retards up there where doing .