Weaknesses of the movie
I think the movie was entertaining. I wanted to know how the story ends. I also liked Javier Bardem's acting.
But there are three major weaknesses in The Sea Inside :
1. It was psychologically somewhat unrealistic.
Everyone who has experienced immobility through an illness or an accident oneself, or knows closely someone who has, will know that one's dread, detestation or aversion towards the wheelchair falls off quickly when you really need it. So Ramon's extreme reluctance - that had lasted for 26 years! - to sit in one is a psychological anomaly; if the Ramon-character really was that strange and an exceptional person in that sense, the reasons for it should have been explored in the movie. The fact that they were not makes me think that this psychological unrealisticness was just based on the ignorance of the auteur.
Plus, Rosa's complete change of mind about the assisted suicide should have been explored a little more. The character was left shallow.
2. At times the movie was overly sentimental in a ...purposeful way, I think.
3. And the worst weakness is that philosophically and ethically the movie completely lacked the Christian view point to euthanasia, even though the story was situated in a traditionally Catholic society.
And no, the fact that one of the characters happened to be dressed in a priest's uniform is not the same as having a Christian perspective. I mean, the priest guy's argument was basically that "living is more than just being able to run...", wtf!? The writer of the story clearly wanted to exclude the sacredness of one's life -view point from the ethical aspects of the story. Why? Because it might have awaken the religious sentiments of the Catholic audience? Making them "remember" euthanasia is a sin?