Codenames: Marvel combines the hit social word game Codenames, while featuring characters and locations from the Marvel Universe including, Spider Man, Guardians of the Galaxy, The Avengers and Doctor Strange. Opposing teams, S.H.I.E.L.D. and Hydra, compete to be the first to identify all of their team's ‘field agents' from 25 Code cards displayed in a 5x5 grid. Code cards contain pictures on one side and words on the other.

In Codenames, two teams compete to see who can guess all of their words correctly first — but those words are hiding in plain sight in a 5x5 grid that includes the words of the other team, neutral words, and an assassin that will cause you to lose the game immediately if you guess it. One person on each team is a spymaster and only these two know which words belong to each team. Spymasters take turns giving one-word clues that can point to multiple words on the board. Their teammates try to guess words of the right colour while avoiding those that belong to the opposing team — and everyone wants to avoid the assassin.