Persona 3 Em is designed as a side-story taking place during the Yakushima trip of Persona 3. It is designed to emulate the original game in having a social-interaction driven daytime period and a dungeon-crawling night period. Dungeon mechanics such as equipping weapons and all out attacks remain the same, as well as the soundtrack. Persona fusion in the Velvet Room is also possible. However, due to the limitations of the cellphone platform, Persona do not level up and must be fused to acquire new skills.