This movie is obviously just another money maker (just to throw that out there). Now by itself this movie is actually pretty good. Not one to go crazy over but a nice little film to watch. But compared to the other pirates films, it just doesn't make (much) sense.
I can't give too much info here or else it might ruin the plot for some. However, the way the movie opens up is a bit scrambled. Characters once known are now introduced being in a position that doesn't really make sense why they are there. It later explains it but it still boggles my mind a bit when trying to figure out the details.
There are moments of romance which at most times it just feels cheesy. It is (I guess) crucial to the story but it just didn't need to be carried out so much or have at least been done a little better (or I'm just being too hard when it comes to this, I don't know).
The story line itself does fit in to the other movies in a way but doesn't really add any more long term change in the characters. It is cool however seeing Blackbeard and his ship, but it still feels like a money maker than anything else.