In the office scene, Paul tells John, "You have finally made my shit list," a reference to "The Machinist", in which Tucker tells Trevor the same line.
Much of both films take place in the protagonists' apartments. Both films feature rotting food and in both cases it's a rotting animal (fish and rabbit respectively). The protagonists of both films are descending into madness. The atmosphere in both is dark and oppressive.
Toward the end of the movie, the protagonist repeats "I know who you are" several times, echoing Harry Angel's realization "I know who I am," also repeated several times toward the end of Alan Parker's film. Also, Ivan's diabolical persona shares ominous characteristics with Louis Cyphre's character.
