There are two stories in this film: one about the crew of the Essex trying to get whale oil while surviving the harsh sea (and meeting a huge whale), and one of the survivors of the event telling Herman Melville, the author of Moby-Dick, about what happened while trying to get past of a certain moment of that event. I find those two stories really compliment each other, and done well.
The danger of the sea is really good. Not only does the crew of the Essex have to deal with a giant whale, but also storms, hunger, morality, sunburn, and injuries. It helps that you genuinely care for the characters (minus a few red-shirts) even if they have basic motivations, and you know that at least one of them survives.
Maybe for some people, they will not like the pacing since it is pretty slow.
If you expect this film to be about people taking on a whale, you will be disappointed since it only appears a few times throughout the whole film.
Since there is a survivor telling the story, I think that kind of ruins the immersion of survival a bit since you know that at least one person survives.
Based on the inspiration for Moby-Dick, this film is great, and other than a few nitpicks, there are barely few errors that I can think that makes me dislike it. Which ends up surprising me when I heard that critics do not really like this film. Even some of my favorite YouTube celebrities (i.e. Jeremy Jahns and Chris Stuckmann) do not like this film at all. I say the reason why is it is the marketing’s fault. They expected to be a movie about a whale when it really is a movie about survival in the sea. I am probably the only one who truly likes this film, so I will leave it at this: if you watch it, you may love or hate it. That is completely up to you. For me, I thought it is one of the best films of the year. I will not recommend it, but I do suggest you think about it before judging it quickly.
I did watch this on 3D Imax, and I think it is all right. The only times that it was effective is during the chaotic moments on the ship and sea. Other than that, not really worth the extra money.