DC Universe References
Throughout the game, many of the thugs Batman encounters will discuss other cities and heroes in the DC universe, including Metropolis, Bludhaven, Keystone and Central City. There are also several buildings owned by other DC heroes and villains.
Catwoman makes reference to having burgled Queen Industries, which is the large corporation owned by Oliver Queen - A.K.A. Green Arrow.
There are several billboards advertising vacation packages to Santa Prisca, which is the home country of the villain Bane. Many Militia members can also be heard referencing the South American country.
Other thugs reference the fact that Gotham beats out Keystone because you can at least see Batman coming, unlike The Flash, who hails from Keystone.