BIOHAZARD A.T.N. ASSAULT THE NIGHTMARE is a video game in the Resident Evil franchise. It was released in 2002 for mobile phones under the NTT DoCoMo operator in Japan. It was sold as part of a subscription to 'Capcom Party' at ¥350 per month. Later, the game was adapted for western mobile phones as well.
— Official description
The game takes place at an isolated mansion on the hills, which is sometimes refereed to as a castle depending on the version of the game. The player controls a police officer who was sent to investigate after the local police precinct received an emergency call (or "SOS signal" in some versions) from there.
After searching around the mansion, the player character is able to unlock a corridor where a licker is fought as the final boss. After defeating the licker, there are four possible endings with the protagonist rescuing a survivor of the incident. The survivor can be a dog, an adult man, a crying woman, or a pair of children.
The game operates as a First Person Shooter, and features the player roaming around the building shooting at zombies and crows. To collect keys or refill ammo and health, the player must shoot green herbs, ammo packs, and items which appear floating on the screen from times to times. The weapons available were the handguns, a shotgun, a submachine gun, and even a grenade launcher.