Very much like Memento, I'm not sure if you can (outside of Nolan spilling the beans, which he won't), even with multiple viewings, know everything for sure.
HIGHLIGHT FOR MAJOR SPOILERS.
Is he still dreaming? Then why are his kids wearing the same clothes in the end? Was he in a dream all along? Is Mal alive ? Why did he let so many people become familiar with his totem ? Wasn't it actually Mals totem anyway, and can he even trust it?
So many questions, damn you Nolan, you've done it again.