Takedown

Takedown is a melee attack in Deus Ex: Human Revolution used to quickly neutralize human NPCs. In contrast with the previous games in the Deus Ex series, this is the only melee "weapon" available to the protagonist, Adam Jensen. A takedown is initiated by pressing the takedown button (default: Q, O for PS3 and B on Xbox) while being within 2 meters of the target and having at least one fully charged energy cell. A cutscene will display Jensen taking down his target with Close Quarter Combat (CQC) moves or, in case of some lethal takedowns, using his arm-blades. This attack cannot be successfully used on bosses (with one exception), as the boss will block and counter it. Otherwise the attack will always succeed against any other type of human NPC.

Overview
The Instant Take-Down augmentation is available by default to augmented Adam Jensen and allows him to engage single enemy. It can be used from the beginning of the mission in Sarif Manufacturing Plant. During the introduction, Jensen does not have this ability, so his only combat option is using firearms. In The Missing Link DLC, the Instant Take-Down is part of Adam's "factory zero" build and can be used from the get-go.

With the Quicksilver Reflex Booster augmentation, Jensen can also take down two targets at once if they are close enough, which yields the normal XP bonuses for the two takedowns with an additional "Two Against One" bonus. A takedown uses one energy cell, whether it's single or double.

Every human enemy is dispatched with the same ease, even the most heavily armored and biggest ones, including Ogres, who can withstand up to 100 shots from a combat rifle, but go down after one punch like everyone else.

Takedown can be lethal or non-lethal, the differences being that:
 * 1) Lethal takes more time to initiate: you have to get near the enemy first, then hold the takedown button for 1 second to start it. Meanwhile, with non-lethal takedown you can mash the button to attack quickly, which can make a crucial difference when confronting heavily armed hostiles in close quarters.
 * 2) Lethal is noticeably louder: its noise radius is ~25 meters, while non-lethal is almost silent (~1 meter). Hence, it's more likely to put the nearby enemies in a "long alert" state; also, if there are alarm panels present on the level, enemies will try to trigger an alarm upon hearing a death scream.
 * 3) Lethal gives less experience: 30 XP for single lethal takedown (compared to 50 XP for non-lethal) and 85 XP for double takedown (compared to 125 XP).
 * 4) Lethal will prevent Pacifist achievement from being awarded.

The game plays exactly the same animation for every enemy type (light/armored, normal/huge). What kind of takedown animation will play is determined by three factors: Attempting to perform a takedown on a boss will cause the boss to counterattack, which will then take off a significant chunk of Adam's health, and should be avoided. Lawrence Barrett will not display a takedown prompt; he will grab and punch Jensen if he gets close enough. Yelena Fedorova will counterattack Jensen's strike with a split kick, even if she's attacked when stunned. Jaron Namir will perform a backflip when engaged normally, but can be defeated in a single takedown if he gets caught while doing a jump over a wall (see the tactics section on character's page).
 * 1) The target's body position. There are 2 positions recognized by the game:
 * 2) *Standing – the most common position. Although visually the target may be leaning against a wall or, for example, laying on a floor after being knocked down by a concussion grenade it will still count as "standing".
 * 3) *Sitting on a chair. There are two animations for this position that play if target is approached from behind: 1 lethal (blade through spine) and 1 non-lethal (choke).
 * 4) Lethal or non-lethal. There are 2 sets of animations with 8-10 animations for each takedown type.
 * 5) The direction targets is facing relative to Jensen's position at the start of takedown. If you approach the target from the back it will be one of the animations from set #1 (neck choke, shoulder tap followed with a punch, blade through spine, etc.), if from the front it'll be the one from set #2 (face punch, neck spin, blade through thigh, etc.). The same principle applies to double takedowns animations, although the direction calculation is a bit more complicated for 2 targets. The game chooses randomly what animation will play from each set: it doesn't matter whether targets are hostile or completely oblivious to Jensen.

Considering that the only resource for takedowns is bio-electric energy which can be recharged indefinitely (one cell at least), the takedowns can be used as a sole weapon throughout the whole game. They're quiet, instant and failure-proof. Even as an addition to other weapons they complement every play style, especially stealth-oriented or pacifist characters.

Performing a takedown for the first time time will earn player the First Takedown achievement. Performing 50 lethal or non-lethal takedowns on hostile characters (not on civilians) will award the player with the Opportunist achievement. Knocking out 100 enemies non-lethally (takedowns included) yields the Consciousness is Over-rated achievement. Considering that there are at least 360 enemies in the game it is possible to earn all three achievements one third into the game, and it's especially easy during a Pacifist playthrough.

Experience
Single takedown: Special experience bonus Two Against One (45 XP) is awarded for double takedowns. Effectively, however, the difference between one double takedown and two single takedowns is 25 XP because Expedient (20) bonus is awarded only once.
 * Lethal (30): Man Down (10), Expedient (20)
 * Non-lethal (50): Man Down (10), Merciful Soul (20), Expedient (20)

Double takedown:
 * Lethal (85): 2x Man Down (10), Expedient (20), Two Against One (45 XP)
 * Non-lethal (125): 2x Man Down (10), 2x Merciful Soul (20), Expedient (20), Two Against One (45 XP)

Dispatching enemies with non-lethal double takedowns is the most efficient way to earn combat XP, giving 125 XP / 2 = 62.5 XP per enemy. Single takedowns are slightly less effective (50 XP).

Double Takedowns Guide
Players interested in extra challenge or trying to maximize their XP might want to perform only non-lethal takedowns on enemies throughout the game — ideally aiming for double takedowns whenever possible, since they give the most experience points per enemy: 125 XP for a double takedown, which is 62.5 XP per enemy (instead of 50 XP for a single takedown). Since non-lethal takedowns produce very little noise they're perfectly suitable for stealthy play-styles. This means that players hungry for XP may want go a little further and try to get Ghost and Smooth Operator bonuses while doing a "clean sweep" of enemies on each level.

This guide is dedicated to this type of "maximalist" playstyle, exploring the methods for manipulating enemies and setting up double takedowns that at the same time preserve the player's stealth status.

Most of the methods listed here are meant to trick a single enemy into moving close enough to another enemy for a DTD while remaining unseen. As you can see on the Ghost page, the criteria for this rating is rather flexible and in no way requires being absolutely stealthy: you can be seen briefly, produce noises, shoot guns, even hurt enemies — and all of this won't count against Ghost. And, as far as human enemies are concerned, Smooth Operator bonus is awarded as a result of fulfilling the Ghost criteria: if enemies won't see the player or their allies' bodies, they won't trigger an alarm.

These methods work well on normal enemies in relaxed state (that appear gray on the radar). Alarmed enemies act differently, but since this is a Ghost guide, enemies are presumed to always remain non-alarmed, i.e. they never go hostile or find a body. Exceptions are the Alice Garden Pods, TYM Penthouse and the Picus Communications building in the main game and the Rifleman Bank Station in The Missing Link, where enemies are in a "permanent alert" state. Generally they react more unpredictably than normal enemies (i.e. check the noise disturbances in pairs), so more caution and less noisy methods are required when dealing with them.

All possible and verified DTDs in the Human Revolution and The Missing Link are listed on their corresponding pages: Experience by area (DX3) and Experience by area (DX3ML).

Use the invisibility cloak and the silent movement augmentations
Stealth augs (cloak and silent movement) are pretty much required for this play-style. They work in combination with every other method and can make a lot of DTDs trivial: like, for example, when player needs to approach two enemies from the front or exploit a brief opportunity for DTD when enemies come close during a patrol. The only risk to Ghost status in this case comes from physically bumping into enemy, which will immediately make him hostile. On resource management side, each takedown consume a single energy cell, so whenever player wants to use the augs in tandem with takedown it will require consuming an energy-recharging item (cyberboost bar, pack or jar) — and there is a limited supply of these items in the game, which prevents their abuse.

Although, it must be noted that there are 40 or less DTD (out of ~166) in Deus Ex: Human Revolution that are very hard to perform without augs, and even then rarely more than one extra energy cell is needed. There are at least ~120 energy cells that can be recharged by consumables found throughout the game, so there is a huge surplus of energy for these augs to be used regularly. All other DTDs (~130) can be done on a single rechargeable cell.

Exploit pre-set opportunities
There are numerous cases where enemies are already placed close enough together for DTD when you first meet them. If they're talking, perform a takedown before they finish their dialogue and separate. Approach them from the back or abuse their limited cone of vision.

Provoke an enemy to move by trespassing a secure zone
Simple and safe method for setting up DTD, but useful only in a handful of places, where enemies are normally friendly (showing green on radar), but issue a warning when player enters a secure zone ("Move away, this doesn't concern you!"), then turn hostile if he does not comply. Although technically enemies see the player, Ghost status won't be canceled until they turn hostile. This method can be used in Derelict Row entrance, MCB's apartment and Belltower blockades in Hengsha.

Lure enemies by throwing physical objects
Noise disturbances that are caused by objects hitting something alert every enemy in their radius (~20-25m). But after a few seconds everyone goes back to normal state except for one enemy who remains alarmed and goes to investigate. There are two set of parameters affecting what he does next.


 * Type of disturbance (aural/visual)
 * If enemy sees a thrown object, i.e. sees it hitting something inside his cone of vision, he will investigate the place object was thrown from. If multiple enemies have seen the object, game usually picks the enemy closest to throwing location to investigate.
 * If enemy heard a noise made by a thrown object, but did not see it, he will investigate the place of a sound disturbance.
 * Object weight (light/heavy)
 * Small and Medium objects cause only a single enemy to remain alert and investigate.
 * Heavy objects (that require Strength aug to lift) sometimes lead two enemies, not one, to investigate the same place together, thus giving a very easy DTD, but are too unreliable to use as a primary method. Single/double investigation is affected by the amount of noise produced and force of the throw but it's difficult to replicate the result on different throws. It may also lead enemies to triggering an alarm, so it's better to avoid them.

Lure enemies to your position by running or jumping in their vicinity
When in limited space or with no objects at hand use Adam's natural noise device — his legs. Jumping, running or sprinting will produce a sound disturbance and lure an enemy to investigate it. AI's reaction is the same as to hearing noise from small/medium object.

Lure enemies with gunshots
A bullet produces a noise when it hits something and this tricks a guard into investigating the point of impact. Surprisingly, enemy seeing or hearing your shots doesn't affect Ghost in any way (bullet noises are treated as small/medium noise disturbance) and won't lead to an alarm. This method may be very useful when you need to lure enemies that are too far away from each other or want them to face a specific direction. It works on bots too if you need to distract them. Obviously this trick requires a silenced weapon (pistol, SMG or rifle), some spare ammo and a safe place to shoot from.

Lure single enemies by visually alerting them
Briefly peeking from cover in 3rd person or, when in first person, quickly moving back and forth from behind cover will alert enemies (they will show up as alarmed on radar) — without any effect on Ghost. Doing it quickly (0.5-1 seconds, depending on distance from enemy), won't turn anyone hostile and will trick enemy into investigate player's last known position instead. This is the most reliable method, since it doesn't require anything besides cover and fine timing; also, enemies' reaction to it is very predictable — it works well even on permanently alerted enemies.

Use one of the DTD's targets as a makeshift cover
A combination of the above "peeking from cover" method plus the fact that human bodies are opaque to AI's vision.

"Roll" a crate to approach the DTD targets unseen
Crouch and push a crate in front of you to approach foes safely and unseen — staying behind the crate at all times, of course. No one will bat an eyelash when they see a box rolling towards them, so this method can work as a substitute for stealth augs (if they're not available) and provide mobile cover. With strength augmentation it is also possible to roll heavy crates. Take note that turning on the invisibility cloak while standing behind the crate will make enemies spot you ("Holy s**t, look at that!") when you as much as nudge a physical object — and this will also negate Ghost rating.

Re-route enemies by blocking their normal patrol paths
This method exploits the fact that AI moves between few static points always using the shortest route possible. Build a "wall" of physical objects (crates, boxes, barrels, dumpsters, fridges, etc.) to block the normal patrol path. When a patrolling enemy can't get from point A to point B of his path using the normal route, he will choose the next shortest path — presumably, one that leads him next to another guard.

Stop an enemy from moving by blocking him with physical objects
A modification of "re-routing" method that requires either completely surrounding an enemy with crates or plugging every hole in his patrol path. If he can't get to any of his patrol points he will just stop and won't move at all until his path gets unblocked. This method is useful when enemies' spawn points are known beforehand.

Perform takedown in a "buffer" zone
In some areas of the game there is an odd number of enemies, so after performing all possible DTD's one enemy will be left without a "partner" for the last DTD. It may be tempting to lure him into another area, but levels in DXHR build in such a way that each enemy will be permanently assigned to a volumetric zone that he can operate within, and which he can't leave under any circumstances. Producing noises or even being seen won't work — it is simply an engine limitation.

Still, there is a workaround to perform a DTD in this situation, which uses a combination of "noise luring" and "crate blocking" methods. It involves bring one of the enemies to a "buffer zone" (border between the zones enemies are assigned to), stopping him from moving back to his default position and then luring another enemy close to him for DTD.

Combine different methods to resolve complex situations
As an example, here are two rather difficult levels from Deus Ex: Human Revolution: Tai Yong Medical Penthouse and Omega Ranch cleared of enemies with double takedowns and Ghost status.