Complicating things is a lot of fun. But, simplifying makes for a good movie philosophy. That whole movie came down to hope? Yes it did. Yes it did.
Hope is a good thing? Maybe even the best of things? It is a strong point. Hopefully Andy is right.
My theory is that Andy did black out. He didn’t know if he killed his wife and her lover. He lived the rest of his life hoping that he didn’t.