The fighting sequence in the hospital is a reference to the movie Oldboy.
The gas station Vincent and Leo are robbing is called "Roy & Roger's", likely a reference to the Swedish musical sitcom Macken (1986) in which the brothers Roy (Anders Eriksson) and Roger (Jan Rippe) own a small car garage and an adjoining self service gas station.
The writer/director of the game and the voice actor for Leo are brothers in real life.
In the Farm House, there is a reference to the popular Nintendo Game Series, The Legend Of Zelda. This cutscene is found in a hidden room where your character pulls a sword out of a chest.
Towards the end when you confront Harvey this is a reference to Scarface.