Coded Arms: Contagion is a direct sequel to the Coded Arms game, and the second game in the series. The player takes on the role of special agent Jacob Grant and enters a virtual reality combat simulation program called A.I.D.A to stabilize it and enable its proper use. After the simulation program previously spread through earth's networks and ran loose, humans had to risk their lives by digitizing their personality, for a chance to hack inside the system and bring back the valuable data inside, guarded by enemies from the military program that was no longer in use. Now that it is contained again, while experimenting Jacob discovers that the program is still not stable.

Like its predecessor, Coded Arms: Contagion is a first-person shooter and it offers over a dozen different weapons that can be upgraded using plug-ins. It is also possible to hack into turrets (by picking they identical number from two lines of data) and turning them against their masters. There are thirteen missions in total. Multiplayer is available on five different maps for up to eight players, supporting both Ad Hoc and Infrastructure.