[[WMG: Most of the final act of the movie happens in Red's head.]]
Andy really hanged himself that night in his cell. Red couldn't accept it and deluded himself into believing that Andy had escaped, hence the many loose ends like Andy using the Randall Stevens alias after breaking out and why was Andy so upset when Warden Norton decided not to investigate Thomas' claim despite having a escape tunnel built all along (something that would get him in deep trouble if it was discovered -- breaking out of jail is illegal, even if you were innocent of the charges that put you in there). Neither the warden nor the head guard were arrested, but Red did get the conditional. He hang himself on the same beam Brooks used, and met Andy in the afterlife.
** Too mean-spirited given the overall tone and message of the movie.
[[WMG: Andy really did kill his wife, and Tommy really was making the whole thing up.]]
Andy was much too drunk the night he followed his wife and her lover to their rendezvous point, and the booze, coupled with his own guilt, blacked out the murder in his mind, to the point where he truly believes himself to be innocent. Tommy really did make up the story of the "real killer" and told the warden he would "tell the truth" on the stand, under the belief that helping to get Andy out of prison would win him points with the guys inside. Considering how important Andy was to the warden's money laundering, the warden didn't want to take any chances, and had Tommy shot.
** That doesn't make any sense. If that were so then that whole Tommy subplot would have been useless.
[[WMG: Andy would have never went to jail if Johnnie Cochran was his lawyer.]]
It was all circumstantial evidence at best, and Johnny would ''never'' of allowed his client on the stand.
** The movie isn't made in modern times
[[WMG: Andy fought in WW2]]
It fits the movie's time frame. It could also be the reason why his wife had an affair: he was emotionally distant from all the things he had seen, so she abandoned him for another lover.
** This is actually (partially) canon in the novella. In the book Andy has a friend on the outside that helps him set up his alias and when Red remarks that he "must have been a pretty close friend" to do something so illegal for him, Andy replies that they were in the war together in occupied France and Germany.
[[WMG: Andy became a criminal]]
Sure he was an innocent man before he came to Shawshank but his time spend corrupted him to the point that he became as crooked as the rest of the cons. That's the real tragedy behind his whole arc. Once an upstanding man now a corrupt criminal on the run from the law. Make more sense than anything else above.
* This is legally confirmed. He did escape the prison, which is a felony.
[[WMG: In addition to being charged with Tommy's murder, Hadley was also charged for Fat Ass's death]]
Hadley's arrest would also result in him being fired and losing his badge, meaning any guards who witnessed him beat the guy to death on Andy's first night at Shawshank would no longer have a reason to keep silent. There was no reason for Hadley to bash Fat Ass's head in, and that would be considered murder of some sort.