You Gotta Shoot 'Em in the Head

You Gotta Shoot 'Em in the Head is a side quest in Fallout 3. It is also an Xbox 360, PC achievement and a PlayStation 3 Trophy.

Background
Allistair Tenpenny once hired five mercenaries;– Mister Crowley, Tara, Dave, Dukov, and Jeff Strayer;– to find a rare weapon in Fort Constantine. In order to get a bigger share of the reward, Dukov trapped Mister Crowley (a ghoul) in a room with feral ghouls. Crowley, who survived despite what everyone else believed, is now a resident of Underworld. Tara died in Fort Constantine and the three remaining Mercenaries escaped and completed the mission.

Starting the quest
Talk to Mister Crowley in the Ninth Circle or at Carol's Place in Underworld. He gives you the task of finding and killing Dave (at the Republic of Dave), Ted Strayer (in Rivet City), Dukov (at Dukov's Place), and Allistair Tenpenny (at Tenpenny Tower). He says they are ghoul-haters, and he wants them each killed with a shot to the head (as zombies are killed in fiction). For that purpose, he will give the player a sniper rifle and five .308 caliber rounds. Crowley offers 100 caps per death by headshot with the sniper rifle as payment. He says that "word will get around" if Tenpenny is killed, but he wants proof for the others: "something personal... like a key or a ring."
 * Crowley will only pay 25 caps for any killing method other than a head shot, but you can lie about the act and get the full price by passing a somewhat difficult speech check. This does not apply to Tenpenny; he must be shot in the head by you to get the full reward, since word of his death would spread rather quickly.
 * Killing anybody grants you negative Karma although killing Tenpenny grants you positive Karma.

Crowley's true motives
Bribing or passing a speech check with any of the named non-player characters in Underworld – Ahzrukhal, Carol, Doctor Barrows, Winthrop, Patchwork, Tulip, or Quinn – will raise doubts about the targets' bigotry. Under questioning, Crowley will admit that he actually wants a special key from each target except Tenpenny. He still wants Tenpenny killed with a shot to the head. Instead of 100 caps per headshot, he will sweeten the deal by offering 100 caps up front plus an additional 100 caps for each key. Mister Crowley's objective is the suit of T-51b power armor still stored at Fort Constantine. You can learn about Fort Constantine and the power armor from Crowley (with a speech check). Other than the additional reward, the conditions of the quest do not change by learning this.

Tenpenny's counter offer
Tell Allistair Tenpenny that Crowley sent you to kill him. Tenpenny will offer 300 caps if you agree to kill Crowley instead.
 * Tenpenny pays 100 caps up front, so it is possible to double-cross him and just pocket the caps.
 * Killing Crowley and returning to Tenpenny for the reward ends the quest.

Getting the keys
The keys can be obtained by speech checks, pickpocketing, or by looting the key from the owner's corpse. They may be collected in any order and can be delivered to Crowley one at a time or all at once.

Jeff Strayer is dead, but his son, Ted Strayer, is now in possession of his father's key. Ted lives in Rivet City.
 * Ted Strayer
 * Ted can be paid for his key.
 * He can be convinced with a speech check.
 * He can be threatened (Strength 6+ or Toughness perk)

Dukov can be found at Dukov's Place.
 * Dukov
 * Dukov can be paid for his key.
 * The Black Widow perk can be used to convince him to give up the key.
 * Male characters with the Lady Killer perk can persuade Fantasia to get the key.
 * Cherry will retrieve the key if the player passes a speech check and agrees to take her to Rivet City. The speech check option appears only once. If you reject taking her to Rivet City you won't get the chance a second time.
 * With a successful speech check, Dukov can be intimidated into giving up the key. However, this speech check is very hard to pass even with a Speech skill of 100. Saving before talking to Dukov is strongly suggested if you choose this method.

Dave can be found at The Republic of Dave.
 * Dave
 * With a speech success, Dave will accept the player as a "Wasteland Ambassador" and present his key as a gift. He will also give you the key if you pass another speech check that is given if you failed the ambassador one.
 * After completing the unmarked quest Election Day in favour of either Rosie or Bob, you can take the key from his body in Old Olney.

Deliver the Keys to Crowley
Kill Allistair Tenpenny and give Mister Crowley all three keys to collect your reward. He will then proceed to Fort Constantine to retrieve the armor. He will return to Underworld after a few days (provided he did not get killed in the Wasteland). At this point you can kill him, which will turn all ghouls in Underworld hostile, or use reverse-pickpocketing in order to obtain the armor (he will be wearing it).
 * Reverse-pickpocketing will be difficult, because the armor has a DR of 50, one of the highest in the game.
 * Crowley may get stuck in bomb storage, even if he had all the keys. You need 100 lockpick skill to open the door.

Retrieve the Armor Yourself
Proceed to Fort Constantine after obtaining the keys. Fort Constantine is located near the northern edge of the map, east of Raven Rock. When you arrive at the fort you will encounter some Brotherhood of Steel Outcasts fighting protectrons and Mister Gutsies. Go to the small house labeled "CO Quarters", located down the hill from Bomb Storage, and head downstairs. In the basement you will find a dead wastelander by an open safe. The door by the safe requires Strayer's key, and allows you access to the Launch Control Bunker. Don't forget to grab the "Bobblehead - Big Guns" from the safe! Continue down the stairs towards Bomb Storage. You gain access here with Dukov's key. Inside the Bomb Storage facility, you will find Tara's body on the opposite of the two Very Hard locked doors. Go to the nearby door, open it with Dave's key and disable the stasis field to acquire the T-51b power armor and T-51b power helmet.

There is a Warhead Storage Key on Tara's body. It unlocks a door that's just up a set of steps from here. This leads to a large room where nuclear warheads are stored, and the area is consequently highly radioactive. This key also opens either of the Very Hard locked doors topside that lead to the Bomb Storage facility.

If you choose this solution, Mister Crowley can still be found in Carol's Place in the Underworld. He does not become hostile, but refuses to interact with the PC anymore, only repeating his line: "You stole what was rightfully mine..."

Deliver the Keys to Crowley and Retrieve the Armor Yourself
Kill Allistair Tenpenny and give Mister Crowley all three keys to collect your reward. Then follow Crowley on his long journey to Fort Constantine. He will require a lot of protection from enemies in the Wasteland or else he will die along the way. Crowley will become hostile upon reaching Fort Constantine, at which point you can kill him to retrieve the keys.

If you don't want to follow Crowley, you can give him the keys and pickpocket them back. You can also go to Fort Constantine first if you've been there already, open all the doors but don't grab the armor, and give Crowley the keys to get the reward. Then fast travel back and grab the armor. Or you can simply follow him into the lobby of the museum and kill him there. You will not lose any Karma
 * If you have Broken Steel installed when giving the keys to Crowley, he will not appear outside the Museum of History. You can fix this problem by waiting by the entrance and skipping 2 in-game hours. Crowley should appear at the entrance and proceed to Fort Constantine. If you have the Point Lookout add-on, then you can also fix this problem if you exit Underworld following Mr. Crowley with the double-barrel shotgun equipped and drawn, then when you arrive in the lobby, he will be there running towards the entrance to the Museum. You have to do the same when exiting the Museum. This may work with other weapons too.

Completing the quest
The quest is marked as completed and the Achievement/Trophy given under any of the following conditions.
 * The player delivers the keys from Dukov, Ted Strayer, and Dave to Mr. Crowley.
 * The player acquires the power armor in Fort Constantine.
 * The player kills Crowley after having been hired by Tenpenny.
 * The player picks up (if previously dropped) or equips (him/herself or his follower PC) the winterized T-51b power armor that was gained from the Anchorage Simulation (glitch).

Bugs

 * After completion of Operation: Anchorage, when picking up the winterized T-51b power armor and equipping it, the trophy/achievement for this quest may suddenly become unlocked. If you drop it from your inventory and do not have a convenient game save, leave it where you dropped it and retrieve it after completing the quest.
 * Mr. Crowley often gets "stuck" while traveling, particularly when swimming.
 * Mr. Crowley may appear at your Megaton house and follow you inside. When speaking with him he acts as if he's still in Underworld. However, once he exits the house and you speak to him as he exits Megaton, he begins saying, "You took what was rightfully mine," without becoming hostile. He then disappears from the game.
 * He may also show up in Megaton hostile, gun drawn, but not firing. All the citizens of Megaton will ignore him.
 * Taking Ted Strayer's Special Key before meeting Crowley may result in being unable to begin the quest.
 * After accepting Allistair's offer and killing Mr. Crowley, Allistair may not have a speech option to finish the quest. If this happens, you can:
 * Repeatedly talk to Tenpenny and he will eventually recognize that Crowley is dead and give you your reward.
 * Take the T-51b power armor from Fort Constantine and complete the quest. If you do this, you will miss out on the reward for killing Crowley.
 * After accepting Allistair's offer and killing Mr. Crowley, Allistair may give you a reward, but the quest will not end. It will keep telling you to collect your reward from Tenpenny. If you talk to Allistair again, he acts as though you have not even mentioned Crowley yet.
 * If you have Bloody Mess and/or the body's head explodes, it will not be registered as a head shot, and you will not be able to receive the full 100 caps for the kill.
 * The quest will sometimes complete itself when switching to a different quest, granting the achievement and registering that you have killed people that you have never met.
 * If you kill Tenpenny, then kill Mr. Crowley, you will not fail the quest. It will tell you to talk to Tenpenny, and then to talk to Crowley, making it impossible to finish the quest.
 * It is possible that when Tenpenny says he will pay you, no caps will be given to you.
 * If you have completed Operation: Anchorage, and continue until the Waters of Life quest, upon exiting Tranquility Lane, you may be informed that you completed "You Gotta Shoot 'em In the Head."
 * It is possible that after completing the quest, Crowley can show up in the Mobile Crawler at Adams Air Force Base.
 * On his way to the Fort, Crowley may get stuck between Underworld and the Mall. This glitch can sometimes be fixed by reentering the underworld and the Ninth Circle, then exiting the museum to the mall Mr Crowley will be there.
 * You may be able to tell Crowley you killed Tenpenny but not have the dialogue option of saying you shot Tenpenny in the head, even if you did.
 * Sometimes when you give Crowley multiple keys, then talk to him about his true motives, the speech dialog only allows you to receive non-headshot kills for 25 caps for every key afterwards, even though he promises 100 per key.
 * If you acquire all keys, turn them in to Mr. Crowley to get the reward, and then kill him, you can take his items off of his corpse. However, if you accepted Tenpenny's counter offer, you will be unable to receive the reward from him. When you talk to him, there is no option to tell him that Crowley is dead, but you can do a speech check (if you haven't done it before) and earn another 200 caps.
 * Giving the Winterized version of the armor to a follower such as Fawkes may cause the mission to be completed. Doing this will cause dialogue with Crowley as though you have completed the mission by taking the T-51b power armor from him.
 * Option to acquire Dukov's Key through "Black Widow" perk does not appear.
 * Killing any of Crowley's targets with the Silenced 10mm Pistol does not count as a headshot kill, regardless of where you shot them.

Behind the scenes

 * The title is a reference to the rule in zombie fiction that zombies must be killed by destroying their brain. Mr. Crowley himself refers to these legends.