I did not notice the film being dark at all. I was actually noticing, particularly in the night on ships deck sequences, that it was ridiculously bright. I figure they wanted the audience to see their neat looking ship in detail and not miss one moment of the pretty cgi ocean in the background... I understand but it really did make the scenes less creepy and more special effectsy. Below decks never looked dark to me either.
Just a thought. Did you view it on a very small screen on a pad or a phone or something? I often wonder if they aren't making films lighter, trying to try to take smaller screens into account - And, if so, sounds like they failed.