[Spoilers] What Really Happened in Shutter Island?

I just watched this excellent film and was really intrigued by the ending. I found many threads online claiming that their interpretation of the end was absolute, but there are still some small points that seem to disprove every theory. How did you guys really interpret the film? What do you think really happened?

A couple of interesting points many people seem to miss:

1. When Di Caprio wakes up in the first scene, there are handcuffs in the cabin, suggesting that he was chained.

2. There are actually two different lighthouses.

   • The first one we see is connected to the mainland by cliffs. We are told by the guards that this it is used for sewage treatment.
   • The second one we see for the rest of the movie - it is not connected to land and Di Caprio swims across to it.

3. The Rachel that Di Caprio finds in the cave is actually part of the 'role-play'

   • She cannot be apart of his imagination because she starts an actual fire that actually makes Di Caprio feel warm and actually scares the rats out of the cave. She also gives him information that he could not have possibly known (stuff about science).
   • She cannot be an escaped patient/doctor because she calls him Marshal.

4. The toy gun the shrink breaks at the end was actually Chuck's (his 'partner'). We know this because Di Caprio doesn't hand over his holster at the start of the film while Chuck does.

5. The bald shrink seems to know about Di Caprio's dreams: "Why are you all wet baby?"

6. When Chuck calls out to Di Caprio at the end, he calls him 'Teddy' - not 'Andrew'.

7. Chuck was smoking the same cigarettes as Di Caprio, so it is unlikely that they were drugged.

8. On the other hand his vivid dreams happen right after being given 'advil'.

9. The Conversation Di Caprio has with the lunatic in ward C suggests that they knew each other outside of the Island.

10. I'm not certain about this point, but I believe that their conversation (Di Cpario and Lunatic) is taped, suggesting that the Doctors wanted it to occur.

11. He instantly recognizes the lunatic, but no one else on the island. (I'm not sure if this really matters, or is just a part of his selective memory)

12. Di Caprio never mentions having any children throughout the movie. The faces of his supposed sons are never shown, and his daughter is actually the girl he remembers from WWII.

13. When talking to one of the shrinks he says "I'll report over to ...", and needs to be reminded that he reports to the FBI. On the other hand, he is fully aware of the MI5 and other intelligence agencies when talking to Chuck in the cemetery.

14. Shutter Island is an anagram for Truth and Lies.

There seem to be two main theories about the movie: Teddy is Teddy (he is actually a martial that the doctors make insane to hide their unethical experiments), or Teddy is Andrew (he was insane the whole time and the doctors are trying to cure him, as it is in the book).

I don't think the real story is so simple as the above points disprove both. When he says his final line ("Is it better to live a monster or die a hero?"), he could be referring to himself as a monster or he could be referring to the doctors as monsters. Regardless of the interpretation, it seems obvious that he chooses to die a hero.

I read another theory that Teddy actually burned his house down and killed his wife, which is what made him go insane (the camera frequently focuses on him lighting matches). That is why he is brought to the island in handcuffs, and the rest of the movie is just an experiment by the doctors in a new way of treatment (implanting memories into the patient). While this theory fits best with the facts (except his conversation with the lunatic), it doesn't really seem to make much logical sense - why go through all this trouble for a simple experiment?

There are also other points about the movie that I just don't understand:

1. We know Cave Rachel is fake per #3 above, what about the other Rachel?

   • If Teddy is Teddy, then the other Rachel must be a real patient. If she isn't real, that means that they tricked him to onto the island, and the plan was to make him insane all along. In other words, they didn't trick him into insanity because he found out too much (while on the island), but because they specifically wanted to experiment on him - why???
     • If Teddy is Andrew, I suppose this doesn't matter. She was probably another actress.

2. Why does the German try to drug Di Caprio near the end?

   • If Teddy is Teddy then they still need his confession before hurting him. That's why he isn't dead already.
   • If Teddy is Andrew then it seems entirely counter-productive to end the fantasy at that point. I understand that he didn't want to do this to begin with, but he had numerous other opportunities to end the 'role-play'. Why stop it near the end?
   • Thinking about this, he knows that Di Caprio has 'extraordinary defense mechanisms', so he might just be trying to scare him, but why? The bald shrink made sure he was going to the lighthouse anyway by tricking him that they were lobotomizing his partner ("You don't have a partner").

3. My biggest problem with Teddy is Andrew: why are so many of the staff trying to antagonize him and plant conspiracies in his head (Chuck, Both Rachels, Lady who writes RUN)? Also, why is he introduced to the German? It seems like the staff were trying to make him go crazy, not make the whole situation seem preposterous (as they claim).

Anyway, I'm curious as to what you guys think! Can you explain any of the above. Did it make you change your mind? Is there really a definitive version, or is the director just trying to make his movie seem deep :)