Something terrible has happened in the perfectly ordinary Karukozaka high school. A resentful student named Hazama made contact with a different universe that co-exists with modern-day Japan. As a result, a demon world emerged within the city, its realms corresponding to the seven deadly sins of the humans. With the help of fellow students, the protagonist must investigate the matter and stop the insane plans of the student.
Shin Megami Tensei If... is a side story within the Megami Tensei universe of role-playing games. Visuals and gameplay are largely based on Shin Megami Tensei. The gameplay system contains typical Megami Tensei features such as demon summoning, demon fusion, and the ability to talk to enemies before (or instead of) fighting them. Enemies will react differently depending on the player's approach during conversation. The battles utilize a turn-based engine. A stand-out feature of this installment is the presence of Guardian Spirits: when the protagonist dies in combat, a supernatural entity will aid him or her, affecting attribute advancement when leveling up.
The game references the 1968 movie If.... starring a young Malcom Mcdowell, which deals with a student rebellion on a British boarding school rife with student abuse and other nasty happenings (though none supernatural).