The quality of the writing creates a nice sense of atmosphere, as when Galan is visiting somewhere with his friend, and the author describes the terrace, the sense of peace, the espresso machine.
Visiting Puerto Rico and going around various places on a boat, you have interest and a sense of place built in, adding to the relationship between the main characters.
The feeling you get from the main dramatic thrust of the story, from the military setting, and from the somewhat staccato dialogue, is of an old-fashioned, early-1950s or World War II Hollywood military movie, with a focus on male friendships and military goals.
I think this would make a good movie, and I wish we had more of the sister in this. This is mainly focused on the men in this story. But the quality of the writing and the setting in "exotic" Puerto Rico really does a lot to open this up.