The Devil Inside is a third-person action horror game in which Dave, a hero with a dark secret, is compelled to participate in a cruel television reality show in which he has to please the audience by killing monsters. Dave has a female demonic alter ego called Deva. The player can transform between Dave and Deva at certain places in the stages. Dave mostly uses guns equipped with laser sights. Deva, on the other hand, casts spells that require magic points, which can be restored by consuming souls left from defeated enemies, as well as float in the air and regenerate her health under specific circumstances.