"Shutter Island"

SPOILER ALERT! NO REALLY!
Okay, just saw "Shutter Island" today. Very well done noirish, suspense-mystery set in the 1950's starring Leonardo Decaprio and Mark Ruffalo. The mystery really makes sense, until the twist ending a la "The Others." Turns out the whole I-gotta-be a hero to save people from government funded brain surgery to turn them into assassins is a hallucination in order to prevent Decaprio's character from believing he had murdered his wife who had drowned their three kids. I feel really manipulated, but I guess that's part of the fun. I still don't get how much was a hallucination, and how much was real. I kinda liked the hallucination story better than the reality.