I really loved the movie Submergence. Its dialogues are quite mature, filming done wonderfully and both James and Alicia deliver very moving performances, with heart-touching chemistry. The love scenes were very passionate!!
The ending is nothing weird of sort, as many of the critics decide to label it. But, it could be said that the ending was of course quite abrupt, rather than systematic as it should have been like the entire movie itself.
I don't know why it didn't do well but I enjoyed it a lot and don't hesitate to watch it repeatedly.