The player will take control of the Asuka ninja Goh, and conduct various missions and tasks, primarily stealth based, for one of three warlords attempting to gain Goh's allegiance. Missions can include assassination, escort duty, protection, theft, kidnap and various others. Missions are delivered by arrow, some of these from "Onji," a mysterious individual who seems to know of Goh's past.
Generally, several missions will be available to the player at any given time, and will sometimes involve locating and claiming one of the soul fragments containing Goh's memories and soul after gaining the trust of a particular lord, who will then advise you of the stone's whereabouts.
As a ninja, Goh is swift, agile and silent, and can use these attributes to his benefit during missions.
Although Goh is a capable combatant, fighting against many enemies at once is ill adviced; try to take them out one by one, if forced into combat the focus on one enemy at a time. Watch out for any soldier reaching for a war horn of a watchtower, as it will warn all enemies in the vicinity of your presence.
Some enemies are much stronger than regular soldiers. Yojimbo, Kenobi Ninja, Mosu Ninja, Taraba Ninja, Bears... Fortunately, these enemies will not call for reinforcements, unfortunately the noise made during combat might still attract other enemies.
Stealth is the core element of the game, and understanding it is neccesary to progress. Crouch behind ledges and walls, climb across rooftops and sneak through canals to avoid detection. This will allow Goh to accomplish his tasks with minimal interference, or until the enemy can be picked off slowly and silently.
Goh can use the landscape to his advantage. By running across walls, soaring across rooftops, using items or keeping a low profile by using obstacles and rainfall, Goh can perform a "stealth kill" on an unsuspecting opponent. These attacks will eliminate an opponent in one fell swoop, although if spotted or heard, the enemy may deflect or prevent the attack.
See Items (Shinobido: Way of the Ninja)
There are many items you can use to facilitate your tasks. Shuriken and caltrops for combat, potions to heal or strengthen yourself, smoke spheres to harm your enemies, landmines to catch them unaware, even poisoned food if you're feeling especially devious.
After reaching a certain point in the story the option of Alchemy crafting is open. This allows you to create your own tools instead of buying or taking them from enemies.
Similarities to Tenchu
Just as the Tenchu series did before it, Shinobido uses a type of "Ki Meter." However, where Tenchu uses a number-based system to judge the distance of an opponent, Shinobido uses a colour-based system to judge the enemy's current status. When approaching an opponent or group of opponents, a pair of eyes will appear at the top of the screen, with an individual set of eyes for each enemy within Goh's range. If the eyes are grey, the enemy is unaware of Goh's presence. Purple eyes indicate that the guard has become alert or cautious due to a noise or having seen something in the distance. Red will indicate that the opponent has identified Goh or one of Goh's allies and is closing to attack. Orange indicates that the enemy has lost sight of Goh, but is still attempting to locate him. The shape of the border around the eyes indicates an individual's status, with different shaped borders for enemies, allies and powerful opponents.
The open-ended nature of Shinobido allows the player to continue the game for as long as they wish to. The game can only advance and finish by selecting story missions. If the player continues to select alternative missions rather than those necessary to advance, the war will be sustained indefinitely or until the player decides to locate all of the soul fragments. Due to this style of gameplay, missions take place in pivotal locations throughout Utakata rather than on unique levels. These locations include commercial hubs such as Sengen Town and Ryonin Market, transport routes such as Dandala Peak and Rokudo Valley and the strongholds of each individual warlord, such as Fudo Castle and Sotai Tower. One mission may have Goh attempting to sabotage a transport cart full of food or weapons bound for the front by attacking the convoy in Rokudo Valley, whilst the next mission may have Goh returning to the same location to exterminate a group of barbarians who are attacking allied convoy shipments.
This also means that these focal points all have their pseudo-realtime ramifications. For example, if there is no rice (if the player stole it or destroyed the cart transporting it) for a particular warlord, his/her soldiers will be less focused, weaker and much less dangerous; repeatedly complaining about their severe hunger and alerting Goh to their positions. If the player opts not to eliminate a rampaging bear in the mountain or forest regions surrounding Utakata in one mission, the beast will likely find its way into the town settlements, leaving the player the responsibility of rectifying the resulting chaos at a later point in gameplay.
Another example would be the omnipresence of the feudal lords. The player may be required to carry out a mission in one lord's stronghold, at the behest of another lord, although this mission will not involve contact or interaction with said opposing lord in any way; they are simply there. Due to this, the player may decide not to comply with the objectives of a given contract and instead choose to carry out his/her own ends. One example would be accepting a contract to steal food, money or documents from the castle of one lord and transporting them to the lord contracting Goh's services; instead, the player may assassinate the lord occupying the castle hardly into the second hour of gameplay. Stealing provisions, assassinating enemies and allies alike in secret and gaining a lord's complete trust so as to eliminate them later is all quite possible. However, such actions require prudent planning and a certain level of skill on the player's part. Nevertheless, the previously set objectives can fail or succeed with Goh's trust with the contracting lord increasing or decreasing depending on the player's choices. The player's imagination and ability are the only restrictions involved in governing each faction towards famine and ruin or power and prosperity.
Witnesses can also be problematic for Goh. Should Goh choose to accept a contract from one lord against another for whom they have worked on many occasions, the latter will feel personally betrayed and likely request his/her troops hunt down and execute Goh. This can become especially tedious if said lord consistently contracts rival ninja or barbarians to attack Goh's hideout. Failure to fend off these attackers will result in Goh's hard-earned money and items being stolen by the enemy, although successfully remaining hidden and earning an "Invisible" rank or eliminating all witnesses at the end of each mission will prevent this from occurring.