I saw this with a co-worker. It's kind of a strange movie and I can see why it is getting mixed reviews.
I would post the description of the movie, but all the information that is given in the synopsis isn't revealed until the last 20 minutes of the film.
This is the frustrating part about the movie. You don't know what's going on. They give you a little bit of info to piece together, but overall you have to pay very close attention and once you figure it out you have to just wait and see if what you have figured out is correct.
I didn't care for it much because I knew where it was going once I figured it out and then kept waiting for a twist.
I'm guessing the people who didn't figure out what was going on liked it and the rest didn't and that's why the reviews are mixed.
I also think the "Merchant of Venice" reference with the title is a bit too obscure and doesn't really go with the movie. There is another element of the movie - jellyfish - which doesn't quite fit with the theme either.
All in all, it wasn't that great of a movie because of the highly frustrating parts of trying to figure out what exactly is going on. Sixth Sense did the same thing, but far less frustrating because you get more info as you go.
In conclusion, it's a rental.