Stealth
There are two major aspects of stealth in this game. One way to avoid contact with enemies is to avoid being seen. Guards aren’t going to attack someone they can’t find or detect, right? Enhance your stealth by staying at long range, using trees and rooftops to keep yourself above guards, and using brush or other forms of cover to hide.
The other method of stealth is to hide in plain sight. High-profile actions, like running around and pushing people out of your way, will draw tons of attention. Low-profile actions, like moving slowly and standing near innocent people, let you chill out while guards walk right past you.
No matter which method of stealth you use, it’s useful to watch the guards. The game lets you know about each enemy’s level of alertness. They’ll have a yellow icon over their heads if they see something strange. A circle fills as the guard gets even more curious. If it gets all the way up, that guard is going to take action.
A red circle is even more ominous. This happens when a guard sees you and is entering an aggressive state. If the circle fills up, they’ll attack you instead of investigating the situation.
The more obvious your actions are and the closer the guard, the faster those circles fill. At really close range, you can be detected in well under a second. At long range, there is enough time to notice, react, and move to cover. That’s your best bet if you aren’t close enough to kill the guard; walk toward cover to break line of sight with the enemy. They’ll lose interest if you do this quickly enough.
Guards who see bodies or suspicious activity will usually approach the area where they last saw trouble. They’ll stick around for a while before losing interest. Either way, wait for them to return to their usual spots or take advantage of the fact that they’ve left their posts. Slip past them by going the long way around, and sprint once you’re safe to quickly leave the location.
When you’re trying to move quickly but are being watched, use a fast walk instead of a sprint. Sprinting is always high profile, and any alert targets will get nervous about that (if they’re already looking for you or are watching a restricted area).
Because guards don’t have great peripheral vision, you can frequently walk beside them and stay unnoticed. This is also effective when approaching to kill them. You can walk up to their side and assassinate them without much delay. In a pinch, you can even sprint toward a target to kill them before they’re able to react. This is risky because their alert status won’t take long to trigger, but it’s viable when you really know what you’re doing.
Blending
It was already mentioned that you can hide around other people by keeping your actions low profile. There is a system in place to let you know when this is working. Look over people’s heads when you’re standing near civilians. A white diamond appears over people who you are blending in with. Guards won’t worry about someone who looks like he’s listening to his buddies. Hang out near civilians to give patrolling guards a chance to walk past you.
Don’t pick anyone’s pockets, sprint, or make aggressive actions while blending. That’s a sure way to get attention and ruin your stealthy cover.
Hiding
If you’re going to be an Assassin, learn how to hide. There are several useful types of hiding spots in the game. Corners let you observe the areas ahead of Shay without stepping into anyone’s line of sight. There’s a good start, but you can do even better than that.
Leaves, hay, and snow are all places where Shay can conceal himself. These don’t work if hostile targets see you jumping into the cover, so make sure that you only do this when no one is around.
If you’re looking on the map, hiding spots appear as blue dots. That lets you know where to go quickly if things are starting to turn against you.
Use hiding spots offensively and defensively. Hide in cover that is next to a guard’s patrol path. Wait for the guard to get close to your cover, and then tap the Assassination button when it becomes available. Shay moves out of the cover, kills his target, and often won’t be seen unless another guard is looking right at that location when you make the attack.
Bushes act as stalking zones. They’re similar to cover in that they break enemy line of sight and allow you to hide while observing the nearby area. You can still launch assassination attacks from them, but there is one extra advantage: You can also use ranged attacks in brush. Line up pistol shots, use Sleeping Darts, or even launch a grenade if you have to. All of these are possible while you’re hiding in brush.
For a stealthy attack, use Sleeping Darts while in a stalking zone, and slip through the guard’s area while he’s unconscious. You don’t even need to kill them.
Getting Away from Trouble
Guards who see through your stealthy approach become alert or even aggressive. Any allied guards who are close by are also given notice, and they’ll join the hunt. Your minimap turns yellow when this happens, and you have to either kill the people responsible to reset the alarm or flee from the targets until they give up.
Smoke Bombs break line of sight and confuse pursuers. They’re a great tool for nonlethal activity. You can also murder people while they’re under the effects of Smoke Bombs, so they’re nice tools to assist with lethal attacks too.
Getting to cover and hiding without being spotted also help you escape combat. When that fails because there are too many people looking at you, you can always rush out of the entire region. Shay is very fit and outpaces most of the guards chasing him. Run as fast as you can and leave the marked yellow pursuit area. Once you’re outside of that, the alert resets and you can return to your business.