Other mistake: During chapter 4, when chasing down the fat mob dude, you step in an elevator. Joe then takes a sip of a whisky bottle, however the bottle is capped.
Bug: There are several occasions throughout the main story where you may find a weapon with an outrageous amount of ammo ready to fire. Such as an M1 Garand with 1020 bullets in its magazine, and unable to reload as it has equal to or more than the amount of bullets at its max, allowing for nearly endless fire.
Factual error: In Joe's Adventures, there is the level called "Supermarket" where the Empire Bay Police Department sends in the SWAT team to confront you. This mission takes place in 1951. SWAT was not invented and utilised until the mid-1960s.
Continuity mistake: Vito is imprisoned in May of '45. He is in prison 17 days when he receives news of his mother's death. The letter is postmarked Jan 25th.
Answer: All made up.