Shin Megami Tensei: Devil Survivor 2 is the second game in Atlus' strategy RPG series for the Nintendo DS. Taking place across six different cities of Japan, the game tasks the player with fighting off an invasion of both aliens and Shin Megami Tensei demons in a post-disaster setting.
Just like its prequel, Devil Survivor 2 is a tactical role-playing game. In combat situations, the player takes turns with computer opponents to defeat enemies and satisfy certain objectives such as helping other characters, while avoiding conditions that will end the mission in failure. In 3 vs 3 battle phase, the battle is presented in first-person and traditional turn based battles, player controls one human and two demons, allowing the player to select one action for each squad member, and the computer doing the same for its squad; combat is then resolved after this selection. Players can get their "Extra Turn" or "Double Extra" in the battle if the player has attacked the enemy's weaknesses or launching critical attacks, and when a leader's health become zero, the battle ends. Also, the player can crack enemy skills. Once cracked, the player can assign these skills across all of their parties' human characters. In addition to demon fusion, the player can acquire new demons, up to 24 in total, by attempting to win demon auctions using the Macca collected in battle.
Outside battle, player can explore the country or save their games. Unlike the first game, Devil Survivor 2 has a new features called "Fate System". Similar to the social link system in Shin Megami Tensei:Persona 3 the players can develop a relationship with the other characters starting at Rank 0, the stronger the relationship, the more that certain character becomes effective in battles. In the sixth day of the game, the player must choose any available endings which the player can unlock by answering some questions from the other characters or help them during battles.
A group of seven unknown invaders called the "Septentrion" suddenly appear and attack Japan on a Sunday after an earthquake strikes Tokyo, which also triggers an influx of demons in its wake. From that moment, skirmishes with the Septentrion occur daily. During this time, a website known as Nicaea also appears, uploading videos that depict the deaths of one's friends prior to their occurrence. To combat the invaders, the protagonist and his friends are forced to make contracts with the newly invading demons and make use of their powers, made only possible after they have one-on-one fights with their first demon and win the right to control them. In all, a group of 13 demon summoners are charged with defeating the Septentrion within seven days, with the ending and main character's standing with the other characters depending on the choices made and fights picked over the course of the week.