While Spoiler:breaking the hostages out of the Special Operatives base in Chapter 4, a Spoiler:Spec-Ops Soldier can be heard falling and screaming. The audio used for the Spoiler:soldier's scream is known as the "Wilhelm Scream", a famous audio clip used in a large number of action movies.
Contributed by Dazz
Inside the church, it's possible to see the funeral of Otis Washington, Frank's security guard contact in the original Dead Rising.
Contributed by EFB01
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A van can be found in the game with a mascot head on the roof. This is the head worn by Brent Ernst, a psychopath from Dead Rising 2.
Contributed by EFB01
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The attack conducted when using The Roaring Thunder, a combined weapon of a battery and a Blanka Mask, is a reference to Blanka's "Electric Thunder" move from the Street Fighter series.
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The Female Business Outfit fully resembles Rebecca Chang's outfit from Dead Rising 2. It is found inside Felicia, located in Central City.
Contributed by Tuli0hWut
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It's possible to obtain the armor of Mega Man X, as well as his Buster Gun, from the Mega Man series. The armor can be obtained by completing the game, while the Buster Gun requires the game to be beaten on Nightmare mode.
Contributed by Funland47
The Dragon Punch combo weapon is a reference the Street Fighter character Ryu, specifically his special move, Shoryuken. When used, Nick will even shout the move's name out loud, similar to Ryu.
Contributed by Tuli0hWut