Fortunately, an English historian is standing up for Mary:
But Leanda de Lisle, author of The Sisters Who Would Be Queen: The tragedy of Mary, Katherine and Lady Jane Grey, said the portrayal of Mary Tudor as a monster was historically inaccurate.
She said: “It really is an example of England’s knee-jerk anti-Catholicism and how our history of the Tudor period has been distorted by post-Reformation propaganda.
“What about Elizabeth? People may be aware of the executions of Catholics, but there were many more people. After the 1569 northern rebellion, Elizabeth ordered that a man was to be hung in every village associated with the rebellions. It was on a similar scale to her father."
The exhibit itself sounds historically inaccurate (from the website):
"Bloody Mary, the deadliest daughter of Henry VIII is ruthlessly ridding the country of heretics.
"In her eyes there is only one faith and all those who believe otherwise must be punished. No one is safe from persecution – men, women and children are all suspect in the eyes of Bloody Mary.
"Feel the force of her wrath, the heat of the flames and the intensity of Mary’s obsession!
"Watch as Bloody Mary punishes non believers
"Punishment and persecution
"Hair raising silence"
According to Mary Tudor, Renaissance Queen, earlier promotion of the exhibit was even more historically inaccurate and "inflammatory"--
“Enter Bloody Mary’s private chapel and witness the fanatically Catholic Queen pass judgment on petrified heretics.”
“Experience the horrifying sights, screams, smells of the most painful method of execution known to man – being slowly burnt alive.”
I don't think the London Dungeon would be on my itinerary for a visit.