This isn't actually a comment, it's a rant...
The movie goes from interesting and mysterious to stupid and idiotic.

[spoiler]3 guys working shifts on the lighthouse of a small island find a small chest with a dozen gold bars, recovered from a salvaged loot that hit their shore. The apparently dead body near their loot isn't dead and tries to murder one of them, but gets killed in the process. They keep the secret and the gold. Soon after two strangers arrive looking for their dead mate, and more importantly, the looted gold. One thing leads to another and they soon become involved in a fight for their lives. After prevailing, a shadow appears outside of the lighthouse... afraid, they chase that figure until the character portrayed by Gerard Butler kills the runner with a swift cut of the neck using his crab-hunting hook. The figure he killed was a ~12yo child, I'm guessing the child came with the two other deceased pirates, even though it's stupid enough. From there on James (GB's char) enters a delusional state that jeopardizes the 3 companions. The rationale behind the steering direction into sheer stupidity wants us to (vaguely) believe that mercury poisoning was somehow involved, although the most stupid character (Gerard Butler's) was not necessarily in direct contact with the substance, and certainly not as much as other characters might have been. Unclear.[/spoiler]

TL;DR: Scenery, music, and acting is great... you enjoy half the movie and then it steers into a great anti-climatic and frustrating 2nd half, ending in the same direction as Gerard's character. I would have unseen the movie if it were possible because the bad parts cancel the good ones. Negative, but candor, a waste of my time - despite the beautiful cinematography.