Every playthrough in an action shooter Contagion never repeats itself, each round is unique, with its own set of resources, weapons and enemies. The main goal is to get out of the city and destroy zombies. Five difficulty levels: easy, normal, hard, extreme and nightmare. Modes in Infection: Escape, Extraction, Hanted, Flatline. There are 12 unique characters to choose from, with different backgrounds, a set of starting weapons, appearance and character.

Some playable characters in Contagion:

• Nicholas L. Glenn – traveled all the time as part of a military detachment. Previously, he was a police officer with an alcohol addiction. Favorite drinks: Scotch.
• Lawrence S. Johnson – Spent 10 years driving a truck around the States, saving what little he had to buy a candy store. Everyone knows him as Larry – the kind, pleasant and balding cook.
• Eugene A. Grant – decided to focus on strengthening his marriage and relationship with his seven-year-old child.
• Marcus K. Lewis – is in the service of the police department, wants to stand out among his colleagues.
• Tony V. Richard – worked as a moneylender, a loner in life who doesn’t need anyone. Relies only on himself.

The gameplay is based on exploring the location, passing levels by shooting back or fighting off zombies in hand-to-hand combat (baseball bat, wrench). There are a total of 4 slots for weapons, of which only two are filled at the start. The action can take place at night (lighting is represented by lamps and a lantern that the protagonist has) or during the day. You can move freely around the city, go indoors, or, on the contrary, try to be on the street.