The game follows an episodic structure, gauged by the Link Navigator, which maps out the events chronologically over three days. Each row chronicles a different hour of the day, and each column represents a character. When a cell is highlighted, a scenario may be played using that character. Some entries are not playable scenarios, only being cutscenes and for this, several characters are not playable. At the start of the game, the player has no control over which scenario to play as the game chooses automatically until a certain point is reached. After this, the player may choose freely.
Gameplay involves controlling a character to meet a known objective stated before play begins. This objective is commonly to reach a certain exit but can be a variety of things such as collecting a certain item or defeating a certain enemy. Moving is limited to running and walking, the latter of which is to reduce footstep noise. The character may or may not be accompanied by an NPC, it is dependant on the scenario. To interact with the environment, players must bring up a seperate sub-menu that contains context-sensitive actions such as 'Open door' or 'Pick up', though the option to 'Shout' is always available (to distract Shibito). The mission fails if your character is killed or the NPC is killed, at which the player may continue from the last checkpoint or restart the level. The player may also examine any area using the action button, which may lead to the character commenting. Players can also crouch at anytime and can also walk while crouching, but very slowly. Every character is also equipped with a flashlight (unless the scenario is during daylight conditions) to see in the darkness, and to examine certain objects. Flashlights are not limited in usage but can be switched off to avoid attracting the attention of the Shibito.
Although stealth is heavily encouraged, a weapon system is implemented. Characters may begin a scenario with a weapon, obtain one during a scenario or lack one throughout. Players may use a quick attack of low power or a slightly longer 'charged' attack with higher power if using melee weapons. Some firearms are used too but only limited to pistols and rifles. Pistols hold varying amounts of ammunition but are usually very powerful. Rifles have lower ammo capacity but have an automatic zoom function for long distance firing. Ammo in the levels is extremely limited, encouraging the player to utilise stealth before weapons.
A unique feature in the game is the ability to 'Sightjack', in which a character can see through the perspective of nearby humans, including the Shibito. Sightjacking requires pressing a button and the screen becomes filled with static, requiring the player to use the analog stick as a tuning dial, until a clear view is achieved. Once locked into a perspective, the player may fix that perspective to one of the face buttons to avoid having to retune to it afterwards. The player can keep up to four different perspectives at one time. The aural and visual quality of the perpective depends upon the distance of the target, with the closer the target, the clearer the signal. While sightjacking, the character cannot move and is thus, vulnerable.
The in-game map displays the surrounding area and the player's directional orientation, though it does not indicate the player's current location (only the start and end points). Instead, the player has to distinguish where he is by orienting himself with certain landmarks on the map.
There are also miscellaneous items scattered throughout each scenario that give the player further insight into the story's background. Once obtained, these items are placed into a catalog called Archives and can be viewed at any time during the game.
Main article: Shibito
The enemies of the game are the Shibito, undead subordinates who roam Hanuda, constructing a Nest for the corporeal form of Datatsushi when he is summoned. Shibito are basically humans who have been exposed to large amount of red water, which regenerates damaged tissue and heals injury, but to the point where their blood has been replaced with it. This gives their skin a very swollen, bluish hue due to their watery exposure and their eyes are characteristically crying blood. The Shibito can never be truly defeated, only rendered unconscious temporarily after sustaining a certain amount of damage.
They are sensitive to sound and will investigate suspicious sounds or footsteps. Once spotted, the Shibito will shout to attract other Shibito's attention and pursue the player, attempting to kill them either with a weapon or by strangulation. Most Shibito patrol on foot, but some are stationary and scan their surroundings with rifles like snipers. After certain point in the game, other variants of Shibito will appear which are much less human and have varying strengths and weaknesses.
A 16-year-old who visits Hanuda in pursuit of a legend in which a mass-murderer massacred over 30 people. Witnessing the ritual in the middle of the woods, he hears the Siren blare and is shot by Tetsuo Ishida, a Shibito policeman. After being rescued by Hisako Yao, he accompanies Miyako Kajiro for the majority of the game.
A 32-year-old professor who was raised in Hanuda, losing his parents to an earthquake cause by a failed ceremony in 1976. Returning with Yoriko Anno, he seeks to discover the truth behind the earthquake only to be caught up in the current events.
A doctor in charge of the local Miyata Clinic. He is the twin of Kei Makino, with whom he has a frosty relationship due to them growing up seperately. Shiro awakens after the Siren in the midst of a forest, with an empty grave in front of him...
Shiro Miyata's twin brother, Kei chose to become a priest of the local Mana religion. After the failure of the 1976 ceremony, Kei is anxious about the upcoming ceremony but is relaxed with Hisako's positive attitude.
At 14-years-old, the blind Miyako has led a sorrowful childhood, due to her being the sacraficial lamb in the ceremony to resurrect Datatsushi. Determined to escape that fate, she flees with her guide dog, Kereb, and eventually relies on Kyoya to save her. Due to the special Kajiro blood, it is impossible for Miyako (or any of her family) to become a Shibito.
A young woman dressed as a nun. She has been in Hanuda since many can remember. She helps an injured Kyoya at the start of the game and she appears very benevolent, but behind this is a sinister objective that she has yet to remember.
A 21-year-old petite woman, Risa visits Hanuda to see her twin sister Mina. After the Siren, Risa finds herself in front of a strange house that has appeared suddenly in the fog.
A teacher at the elementary school, Reiko lost her daughter during a freak sea-wave many years ago. She finds herself trapped in the school with Harumi Yomoda, a schoolgirl, with whom she harbours maternal feelings for in place of her own lost daughter.
A ten-year old girl with some small psychic powers. After losing her parents when lightning struck their car, Harumi lives with her aunt. Harumi is the only resident in Hanuda who acted kindly to Miyako, even becoming her friend.
A student under Tamon, Yoriko harbours a big crush on her professor. She has a tough personality but she is fearful of the dire circumstances she finds herself in.
A big celebrity in Japan, Naoko is both vain and ruthless. She fears that her time in Hanuda will lead to grey hairs. Despite this outlook, she is brave enough to fight her way out of the situation when confronted by the Shibito.
A 70-year-old hunter, Akira is suspicious of Hisako Yao due to the fact that she hasn't aged in years. He is well aware of the religious activity in the village and vows to put a stop to it, having lost friends and family to the occurances.
A fourteen year old schoolgirl who ran away from home because her parents read her diary. Tomoko regrets the decision now that she is entangled in the events.
Risa's twin sister and the love of Shiro Miyata, Mina works in the Miyata clinic as a nurse. Unfortunately, by the game's start she has already become a Shibito and causes repeated trouble for the characters.
The adoptive son of the Kajiro family, Jun was brought in as a husband for Ayako to carry on the Kajiro bloodline. He assists Hisako in her religious objective.
Miyako's sister. She detests her sister for the inferior status she holds in the family, and the fact that the ceremony could bring negative consequences. Despite the fact that she is of Kajiro lineage, Ayako does not know of her protection against transformation.
- Mr and Mrs Maeda
The parents of Tomoko Maeda, they come looking for their daughter in Hanuda. Obviously, they are worried for their daughter's safety and consult Hisako for help.
A local policeman who enjoys alcoholic drinks. After winning a sake-tasting contest, it appears he becomes severely intoxicated and violently assaults Kyoya, attempting to shoot him.
Miyako's guide dog, Kereb is literally her eyes due to the fact that Miyako can naturally Sightjack.
Rather than employ traditional facial animation methods with polygonal transformation, images of real human faces were captured from eight different angles and superimposed onto the character models. This eerie effect is similar to projecting film onto the blank face of a mannequin, a technique used to animate a severed head in Disney's Haunted Mansion attraction.
Silent Hill connectionEdit
The most notable aspect of Sirens development is that it was co-conceived and directed by Keiichirō Toyama, who had previously directed the original Silent Hill. Other former members of Team Silent, Naoko Satō and Isao Takahashi, also had critical roles in Sirens creation.