Code Name: S.T.E.A.M. is a turn-based strategy game for the Nintendo 3DS.The game is played as a turn-based strategy game, with elements of a third person shooter. The gameplay involves a team of characters facing off against an opposing team of aliens, with each team taking it in turns to maneuver and attack that requires the use of "steam", which depletes whenever a character moves around or uses one of its ability. By saving steam, the player can set up attacks that can interrupt an enemy during their turn, cutting their turn short and granting the player bonuses.
Additionally, each character has a single move that can be used once per level that doesn't cost steam. Fallen characters can be revived with medals, but the game ends if all characters are defeated.
Scanning amiibo in this game will allow players to play as Fire Emblem characters. If they die in battle, these chracters can't be revived until the level is cleared (unless the entire party is wiped out). They can be added in by tapping them on the screen.
Each amiibo character uses weapons exclusive to them and that reflect their abilities in the Fire Emblem series. For example, Marth uses his Falchion Blade, while Robin uses tomes to conjure magic attacks.