I'm actually glad I read the reviews before I watched this film. In my opinion the posted reviews by "accredited" sources were predominantly negative, so I went in with low expectations.
I was very pleasantly surprised with the results! I heard this film referred to as an "Alien knockoff" and being an enormous fan of the entirety of the Alien franchise, I had this in the back of my mind while I watched.
So to the review, and I'll try to be spoiler free:
Jump scares: check
Suspense: check
Entertainment: check
The film wastes no time in going from zero to sixty with disaster and action. No beating around the bush, you are introduced to the primary character and boom, you're now racing for your life. The acting and screenwriting give you a pretty brief but effective introduction to the characters and the lack of expansion is warranted, they need to make a decision and move out. Welcome to the decisive Captain. Throughout the terror and suspense you do indeed get to understand who the cast of characters, and yes, although standard and diverse as expected, it really works. The characters are strong, flawed, sarcastic, humorous, self sacrificial and inexperienced as you would expect from a story with some depth. The long and intense journey makes sense considering the situation and the tribulations along the way may be expected, but are well done. The antagonists are scary, brutal and powerful.
Overall I thoroughly enjoyed the journey. Sure it seemed rushed in a few places, but I was easily able to connect the dots. The climax "boss level" antagonist was terrifying and interesting. Considering this was an underwater adventure, and I'm a huge Lovecraft fan, I was quite satisfied with the entire film.
I believe some of the "professional" critics were a little harder on the film than was necessary. I get that a lot of them dislike Stewart, and the familiar facial expressions are there, but honestly; this movie banged and will go in my collection.