Clone and/or some kind of robot/cyborg replacement. Like, the tropical island he keeps remembering is a false memory planted in his brain. He was actually being cloned, or having his killed dead parts replaced with robot parts. That's my dark theory anyway.

On one hand I'd like something like that, but then on the other, it'd be funny to have all this tense build up and have the pay off be some kind of joke.

Do you have any theories?