Plot hole: When the warden comes into the cell the morning after the escape, the poster covering the hole is fastened down on all four corners - impossible to do after squeezing into that small hole. [On the DVD commentary, the director confirms that this was a movie "cheat".] (01:49:05)
Trivia: The Humane Society had to be present for the scene when the maggot is feed to the bird, Jake. The Society said it was cruel to the maggot, so it had to get a maggot that died of natural causes before the crew could shoot it.
Continuity mistake: When the warden is given a bribe by his contractor/buddy, it comes in a box containing a pie and the pie is in a disposable corrugated aluminium pie tin. The warden gives the pie to Andy in a later scene and when Andy and Red eat it, it is in a metal pie pan... the non-disposable kind. (01:06:05)