Character mistake: When De Niro says to Nolte even a hypothetical $50,000 offer sums to about $10 dollars a day in prison, which is correct, he mistakenly claims you divide the 5,000 days by 50,000 (as opposed to dividing $50,000 by 5,000 days). This may also be viewed as a deliberate mistake, a subtle message he is not an actual intellectual.
Character mistake: When Chucky is looking up the information about Andy on the computer, the word juvenile is misspelled "juvinile."
Character mistake: In the very first scene, in the first shot you see a sign in Spanish that says "NO PASE por orden del departamento de arquiologia". The correct Spanish word is arqueologia.