Here is an overview of the game, via its Steam page:
The Craziest Shooter Yet!
Help swarms of girls escape their demon possessions by using your Pheromone Shot gadget for euphoric exorcisms.
A Gorgeous New Cast!
Woo the girl of your dreams in a twisting, turning story full of surprises. With the aid of alluring angel Risu, become romantically entangled with girl-next-door Chiru and childhood sweetheart Nanako.
Become a Knight in Shining Armor!
Manage your schedule to receive quests from the academy’s love-struck girls, and satisfy their demands to unlock new missions and story scenes.
Harness the Power of Vacuuming!
Equip the awesome Demon Sweeper gadget, capable of sucking up Gal*Gun 2’s pesky demon menaces… and perhaps some clothing too!
Full Motion Controls
Throw yourself into the middle of the action, and beware approaches from all angles!
Watch the Steam launch trailer below.