The game features a day/night cycle. During the day, the player is in human form and can walk around freely throughout the game's representation of London looking for the family members who cursed him, exploring, and collecting items. When night falls, he reverts to his werewolf form. In this form he can jump great distances and eat any human he comes across to regain health. However, the game's police force will attack the player on sight when he is in this form. The moment he changes back, they immediately stop attacking. Each time the player kills anyone, the police presence increases.
The game takes place in a multi-room representation of the streets of London, also including rooftops, subway stations and subway tracks.
There are two kinds of policemen who will try to stop the player whenever they see him in werewolf form. Armed police have guns and will attempt to shoot the player. Hand-cuff wielding police will immediately send the player to prison and take away all of his carried items if he touches him. Being imprisoned in this way can be deadly if the player has been shot first; shooting causes a bleed effect which will slowly drain the player's blood gauge. Being shot repeatedly increases the rate of blood loss. There are two ways to stop this bleeding - by using a bandage or transforming back to human form at the end of the night. However, this transformation cannot heal wounds if the player has been shot too many times, leaving with no choice but to find a bandage. The blood gauge can be restored by eating people.
There are a number of useful items to be found throughout the game. Some will always be found in the same places whenever the game is played, while others have a chance to be dropped when killing various humans. For example, killing a policeman equipped with hand-cuffs gives a chance to drop a key, which can be used to get through locked doors. Other useful items include a file which can be used to escape from prison, a crowbar which can be used to open manholes, bandages which can be used to stop bleeding, and so on.
The player's progress through the game is tracked by seven crosses which appear at the bottom of the screen. When the player is close to a family member he must destroy, the cross begins to flash. Once he kills them, it stops flashing and remains visible permanently. Do this for all seven crosses and the game is won. However, the frequency of finding family members decreases with each one killed, and as the police presence in the game gradually increases due to killing, the game can become quite difficult towards the end.