Tomb Raider

I cannot the enemies to respawn... any ideas?

Thanks for making the video SiebeTolsma ,Its great so I've included it in the solution

@ tntiseverywere Do you just mean spawn? once they spawn they should keep respawning once they're killed.

@Wrongway1985 i killed anyone i could find in Shantytown and now there are no enemies at all. I searched every inch of the map (because i think you need to kill the existing in order to respawn in another location) i manage to get 6 kills on ziplines but it seems i need more..

The guys at the top spawn there before the end of the game, so you don't need to finish the game first.

All enemies are respawning in Shantytown except the ones in the tower >.>

@tntiseverywhere once enemies spawn in that location dont leave map they should reappear once killed, no need to search every inch of the map its only that location you should be worried about.

@Ham Salad Didnt know as I had completed it personally thanks for the info.

@Gerbasgamer All enemies? thats odd often heard of none spawning could you get them to follow you off the ziplines then or they're appearing on the ground is it?

I can repeat the process shown in the video until there is a pile of dead guys 20 deep, and still dont get the achievement... It is very buggy and im done pi$$ing around with it. Sigh... I also played through the game again and didnt get this achievement. Done. Great game, but man getting these achievements to pop is crazy.

@rickwh have u died in between some kills as count will reset if games not saved , head over to the bonfire every 2-3 kills if thats the case prob needed if playing on hard.

I'm playing on XBOX and there is an error in the rendering of the zip line. The bottom part of the zipline (arrow attached at the bottom) is just floating in mid air a bit below the rope wrapped around the wood sticking out of the roof of the "shed". Does anyone else on XBOX see this. It isn't rendered that way in the above video.

@richwh I personally killed them loads of times and never had an issue youve tried re-entering the zone a few times right? I see you've missed the chatterbox achievement which would require another playthrough anyway maybe worry about this should u go for another runthrough.

This worked great for me after finishing the game, I used the exact same spot to get the "Get Over Here" achievement for rope pulling guys to their death. Thanks!

@wrongway finally got this ach. Had to play thru game again though. I am convinced my saved game was hosed. :-) Anyways thanks for this awesome tip. Im also going for the major pain in the a$$ chatterbox with this one too. Two birds one stone... Thx

Just wanted to say thanks for this guide! This is the ONLY spot in my game where enemies would always respawn. Also would like to note that this cheevo is maybe a bit buggy; by the time it popped I had more like 20 guys shot off ziplines.

Worked a treat, thanks.

This sucks. Ennemies appear anywhere else but at that point. I've tried reloading it several times. Do the ennemies, at one point, come up to that point? Mine are always downstairs.

The only ones that count are the ones where you shoot them and they fall and die on impact of the ground. The problem is all of your guns are powerful so you kill them in one shot. I had to use the shotgun to knock them off.

@DeathR0t I had to re-route the wire myself after I completed the game as it wasn't positioned correctly that's what you need to do, enemies should spawn and try attack as you re-route just ignore them descend rope and away you go. Don't assume its impossible try it out, hope this helps!

Best solution for this. I would go up there and get their attention. The zip line down. They would follow, so I would kill them. Then I would go back up and they had respawned instantly.

i've got another non spawner here. restarted several times ,cleared cache and fast traveled to and from helicopter hill loads of time and they are still not spawning in the correct place. :(

@halder001 Same here.... About to snap lol.

i gave positive feedback, but the game is buggy, I have the perfect set up, the guys follow me down the line, i shoot them off, i'm at over 50 kills, I HAVE NOT DIED even once, and traveled every 10 kills or so to save them game. Then re-travel back to shantytown. I even did 40 cumulative in a row without dying and still no cheevo! grrrr.. its annoying, and NO other achievement in the whole game has bugged other than this one it's been flawless. Hats off for the solution though.

It simple doesn't work. I had to route the wire and then they never respawn again.

I was having a lot of trouble with this myself- I hadn't set up the rope so I had to do it when the enemies were still there, so I climbed around and waited until they were done with their dialog and walked away to set it up. I was successful and went to respawn the enemies and died. The next time I decided to just kill them and set it, but when I did that they did not spawn anymore- it seems to be they can't be killed when on the tower, I had even tried traveling to other locations and returning to no avail. So I switched to another account and after finally setting it and getting away, I saved the game and was able to get the achievement. Not sure if the game just glitched or their location of being killed actually effects the respawn.

Ditto on not being able to get them to respawn. No matter where I go or how much time passes, the enemies never return. Glad this has worked for some but it's definitely not an all-inclusive solution.

Looks like another playthrough for me. Can't get them to respawn.

I think Bhaine23 is right, our weapons might be too powerful thus killing them before they hit the ground.

Ok, so this is how it worked for me. Ive completed the game, walked to that tower (havent got zip line before attached), and attached zip line. On the top of the tower there was 2 enemies just like in the video. So i was doing excactly the same like in this video. I killed maybe 20 without dying and nothing. Then i stardet aiming for headshots. I killed 10 times and cheevo popped up. So u have to aim for headshots to kill them while they are on the rope, not killing by the fall!

These guys never spawn up there. It's so frustrating I don't know what I am doing wrong

I managed to get the respawn no problem, even after killing the guards on the tower and resetting the rope a few times...however, after about 40 minutes, no achievement! Ryozenzuzex has a comment on another guide saying that head shots are the way to go and I can confirm that this worked for me, having previously been trying to get them killed by the fall. Hope that helps!

Thanks for the solution. I can confirm the headshot theory. I killed plenty of dudes and then after reading the comments tried headshots. After three more confirmed headshots (with rifle) it popped. So if you are having trouble try headshots without dying.

they spawned once and havent since. does anyone know how long into the story id have to play to get 10?

Well since you may need to get head shots, it may depend on how good of a shot you are. But I think the part where (spoiler alert) Grim dies is probably the place.

Also since it is called dead eye it kinda makes sense that some headshots may be needed. Has anyone confirmed that you do not need the head shots (i.e. have it pop after killing a guy sans headshot)?

Is there any solution how to make them respawn again? I beat the game, came back to that place, had 2 guys in the tower, went up there, shot an arrow, killed the guys, went back down but none of them respawned. So i load the game, tried traveling and lots of other stuff but i can't make them respawn.. Any ideas?

There is no consistent way of respawning ennemies as they usually don't. I'm sorry but I guess you're gonna have to start a new game. I had to myself for this very same achievement.

Anyone know if this can be done in MP ?

Hey Harme who are you kidding? I answered to your two previous messages just above. Stop the copy/paste.

Phew! Worked a charm! Thank you!!

What the hell is with this Harme guy? Anyway, this carries over across multiple walkthroughs. It's actually faster to play through the campaign again racking up the kills, then to frustrate over the lack of endgame enemy.

It worked me for killing about 4 enemies , but somehow they stoped respawning. Some people asked me if the kill count through the saves , the answer is : unfortunately no. What did I do ? i started the game again, on easy , and focused on all enemies on the zipping lines that I saw and when I arrived Shanty Town I got all the 10 kills.

Has anyone confirmed that you do not need the head shots (i.e. have it pop after killing a guy by hitting him anywhere but the head??

I'm right near the end of the game and don't have the achievements so this is really gonna come in handy :)

Thanks for the guide

In my case, both shooting at their heads for insta kills or shooting at their bodies to make them drop worked, though it only popped on my 12th kill (4 kills from headshots and 8 kills from dropping)

not sure why anyone down voted this. +1+1+1+1

Want to add that I also needed head shots. Put about 30 down and only after going for head shots did it unlock. Might have just been luck, but I would recommend going for head shots if your not unlocking the achievement.

lol guys, i haven't asked that question before, i was reading through the posts but couldn't find a solution to my problem, so i was asking.. only once, you should read up the names maybe? stop mixing me up with someone else, thank you.
however, i guess i have to restart, damn it.

No soldiers for me neither. So its obvoiusly glitchy which is a shame but im not playing tru for a third time thats for sure.

Great guide. I had to set the rope after beating the game. Killed maybe 16-20 finally popped off of a headshot.

First time I did this I got the enemies to spawn. After killing them I tried to go back up and the enemies wouldn't spawn. Then I re-entered shantytown and it spawned me at the top where the enemies were. Everytime I go back into shantytown the enemies don't spawn anymore. I've tried this during the day and at night and nothing seems to work

I had absolutely no luck with the solution, because the enemys never spawned at this postion.

I started a new game and after 2 - 3 hours i was in shanty town and got the achievement.
So starting a new game is not THAT bad as it sounds... of course it still sucks a bit.

This didn't work for me after my first play through. It did, however, work on my second play through (missed chatterbox the first time too). I don't know what I did differently the second time, so it seems to be pot luck.

DON'T spend time trying to get those two guards in the Shanky town tower to spawn; they didn't show up even once for me post-game despite reentering the area around 30 times. As soon as I switched over to an older non-post game file they showed up immediately.

For me only one of the guards usually chose to use the zipline; the other one went over to my parts on foot, so I just shot crippled and killed him to work towards the dodge incapacitation achievements meanwhile. Also, you don't need to get the "headshot" message for the zipline kills to count, but I cannot say if you need to hit the head since it seemed like I did it when the achievement popped.

Indeed. I've tried dozens of times, both before and after beating the game. The guys in Shantytown simply will not re-spawn for me. Frustrating.

@Guds, so you think you do need the headshot, but don't need the headshot notification? Thanks.

Maybe I missed it but has anyone shot a dude in the belly and popped this? It seems that only DracoKall could have possibly popped it without a headshot but he didn't say which type of shot ended up popping it so I am not sure. Anyone? Thanks.

So I missed this on Xbox one version, and killed 14 using your method and no achievement, but 3 headshots and bam it popped thanks

I popped it on a shotgun blast, non-headshot, popped when he hit the ground (delayed XP notification and everything). Shit is just buggy.

I can verify this solution works, after completing the game, in the Xbox One Definitive Edition! Thanks for the solution! +1

I just want to add that I was having trouble with this as well until I started going for headshots. I had killed probably 30 or so with no achievement until I tried headshots and then got it after 7 kills.

Should also point out it was on the xbox one.

head shots worked for me

This isn't working for me. They aren't spawning there and the enemies can't climb or follow you. Tried doing it legit during the campaign but they're such retaded AI, in such a fantastic game!

What about using this method for the former adventurer achievement? If you've completed the game already but haven't got the achievement.

Just answered my own question, it works. Awesome. Just let them come down the rope, and dodge counter them.

You gotta use headshots. Finally pinged for me using headshots with the bow.

Hello,

I did the same that slimebag44 did I killed them in their tower! and they won't respawn -_- I don't have an older save so what do I do?

I can't get anybody to spawn in the shanty town full stop.......

Got this on the aerial lift to the beach. didn't do any headshots

Thank god! Yes! I had to try 3 different saves at different points in the game (my 100% save didn't work but my 95% did) but I got it where they were at the top. The trick is when they are up there to make sure its all done in one go! Thank god.

Unfortunately this does not work post completion. I've tried getting them to spawn but after the first time no enemies ever respawn. I've searched all the area's in the game and they are all empty. The only place where enemies keep respawning in in the caverns in the pit with cannibals. Those locked up in cages keep respawning. So at least i can use them for kills with certain weapons, but pulling enemies of ledges or shooting them from zip lines is off course not going to work there. I think i have to restart the whole game. Oh well, i already had to since i missed a conversation for Chatterbox.

can this be done in multiplayer?

Worked a treat. I did it at Night and it worked well, but would be better in Day so they are easier to see +1

Just curious but can this be done accumalitive or does it have to be done all at the same time?

I did this after completion. I needed 10 all in the same session even though I'd got at least 5 before during the game. I did not need all headshots either.

100% completion missed this one. Your guide was most appreciated. I was wandering around and there were no enemies that were in correct position. Thank you for the input. Like in the video peek out and get creative. Got a few in the head on the way down.

These 2 guards can also be used for GET OVER HERE. (pulling 5 enemies off ledges)

i can´t get to respawn those guys !!!!

i can´t get to respawn those guys !!!!

Worked a treat, thx.

@Panzer & Bean; sometimes they never respawn, the same thing happens in the XB1 version too. All the Tomb Raider games are full of bugs which Crystal Dynamics can never be bothered to fix.

45 kills, no pop :(

I'm not having issues with these guys respawning but I've killed them both about 50 times and still no achievement I've tried shooting with arrows and I've tried using guns. Nothing works. :(

Just finished this. Headshots is definitely the way to go.

Came back to this after several years and used the pistol. Popped on a headshot.

they won't show up at all for me

I also can't get the enemies to show up (beaten game already).

From what I have gathered though, you can't kill yourself after finding guys to farm either. I tried doing this towards the end of the game by killing the same set of 4 guardian soldiers over and over and then jumping off a ledge myself. I must have killed 40 enemies this with no achievement. Not sure if you need to go "save" at a campfire/quit to menu but it definitely seems like dying resets the counter in some way.

Hope this helps.

Man this one was a pain. Out of my three saves only one had men spawn up the top of the tower. Tip, if you can, copy your save to a USB as a backup! If you accidentally kill one after ascending to get their attention, they stop spawning. Luckily I did this, restored it and continued on. Only other advice is, after you kill them (headshots) don’t reload checkpoint or die, just ascend up the rope again, two new guys will spawn. I hid behind the building, and aimed my pistol at the rope, so when they slid down it was already aimed. Didn’t take too long after finding a save that worked.

Man this one was a pain. Out of my three saves only one had men spawn up the top of the tower. Tip, if you can, copy your save to a USB as a backup! If you accidentally kill one after ascending to get their attention, they stop spawning. Luckily I did this, restored it and continued on. Only other advice is, after you kill them (headshots) don’t reload checkpoint or die, just ascend up the rope again, two new guys will spawn. I hid behind the building, and aimed my pistol at the rope, so when they slid down it was already aimed. Didn’t take too long after finding a save that worked.

This is an awesome guide -- I thought I had to start all over again as well. Thanks! As a bonus, I made a quick video showing this technique. Feel free to use it in your guide!

http://www.youtube.com/watch?v=_ygkXnXCMeQ&feature=....be

@Wrongway Thanks. I'll admit that I have died a few times when cycling though this process. Mostly because sometimes she doesn't grab the zip line as I'm jumping from the upper platform.
Do you think it resets it to 0 or back to the count it was at the last time i saved? In other words do you think the achievement is for 10 dudes within one "life". If so I think I've done that too.
When I had the pile of 20 dead dudes, I was walking back out thru the gate in Shanty town (until I saw the TR save symbol) every so often.
I saw other posts saying perhaps you had to do head-shots so they die on the zip line instead of die from falling. Perhaps that is something to try.
Frustrating to say the least.

@rickwh Go to top of tower (where enemies spawn) just ignore (for now) look down facing "shed"and replant the zipline to match one in video?

@wrongway. Replanting zipline fixed the rendering bug. But by killing the two dudes at the top instead of making them chase me down the zipline.... The game saved and now nothing spawns for me. I think i locked myself out of getting the ach with this save.

@Wrongway, I am sorry my friend, but after the game is completed you simply cannot get those guys to spawn on the tower. I have relocated myself at the tents to various places, including restarting my 360 completely to see if that would make a change. The only asterix to my resolve would be that you MUST have the rope already there attached before you beat the game. If you beat it without the rope attached, I can only assume it is impossible. Please delete your header in the solution **SOLUTION FOR THOSE WHO HAVE COMPLETED THE GAME** because it is incorrect, but thank you for your valiant efforts and vid. Game on.

My experience: went to this area, didn't already have the zip line. Killed the guys on the tower to set it up, and then they would never respawn. I had another save right at the end of the game, so I loaded that up. This time when I went to the area I created the zip line without killing the enemies, and they would respawn. I'm certain that making sure they die off the tower is vital to making sure they continue to respawn - kill them on the tower and they are gone for good!

When I did get the achievement in the end it was with a headshot kill as well, shooting them off the line didn't seem to be working.

Hope that helps people!

Well this is what I figured out.
I loaded up Helicopter Hill. Went to the location. Did not have the right rope to their roof. Went up there. Killed the 2. Then connected the rope. Slid down. Went back up. No respawn. Restarted the game. No respawn. Did this for an hour or so. No respawn.

Then I loaded up an older game. Went back to the same spot.
This time I did not kill the 2 guys first. I went up. Connected the rope. Slid down.
They followed. Head shot them as they came down. Sometimes 1 of them would climb down instead of using the zipline. As long as you kill them away from their tower. They will respawn.
Rinse and repeat.
This works. Just dont kill them in the tower, or you will lose their respawn.
Hope this helps guys.

work after the story?? ive shot 30 ennemies off the line but no cheevo pop for me....i dont want to restart the game

So my experience will hopefully help somebody. I loaded up my 100% save and went to the Shantytown. There I killed the two guys up the tower when trying to connect the zip line. Like people have said before, Big mistake they did not respawn after that. On top off that, nobody spawned for me in the Town. It was as if I finally killed off every one on the Island.

So I backed out and loaded my 76% completed game. On this save I completed the story and that's it. Didn't finish all the weapons, collectibles and skills. So with that save I lured the two guys down. Went to the top, hooked up the zip line, killed them and then went up the zip line. Guys are there again. I must have missed like two or so because I killed 3 on the zip line and got the achievement.

It popped on a kill on the zip line not on fall damage. So I don't know if it's just shooting off or killing. But if you wanna be safe just aim for the head :)

So TL:DR If you have killed those guys on top off the towers they will probably not respawn on you. Especially if you have a 100%. Having only done the story and still have not upgraded everything. You have a good change that this works for you. (Unless you killed the guys probably)

I was able to get the enemies to respawn just by shooting a weapon once, staying at the bottom of the zipline. This also increased the number of times that I managed to get both enemies to come down the zipline. It's a pretty handy tactic.

Unfortunately, like many others, it doesn't seem to matter how many of them I knock off the zipline, the achievement never pops. I believe I can tell the difference between killing someone with the weapon and them dying from hitting the ground, based on when the experience is awarded. If I unload on someone with the rifle, for instance, they die and I receive XP immediately, as they fall. If I hit them in the body with a single uncharged bow shot, they fall and don't die until they hit the ground - half the time they're actually yelling something on the way down. It doesn't seem to matter, though. I've killed dozens of these guys various ways and the achievement won't pop.

Night or day, i cant get them to spawn on that tower, afetr finishing gane i came here for an idea cos i just didnt want to do a whole playthru again, when i spawned at the camp i had to re-establish the zipwire ! While i was trying to do that the dudes on the tower always killed me b4 i could attach the wire to the post on the roof below, so when i got to the top of the tower i HAD to, kno other way round it, Had to kill the guys at the top of the tower so i had time to get my wire attached ! After that i went up and downn, repeat repeat, no one spawned, i went to the fire to save so at least my zipwire was attached when i tried again. I have had the pigs and chickens spawning, even some ground 'soldiers' like the guy u hear talking about 'Her being somewhere' when its his pet rat he is talkin about, ive did it day and night, repeatedly left game and staarted again but there is never anyone at the ttop of the tower, any ideas?

I would also stress the need to get this achievement done before the other kill achievements. In post-game free roam enemies never used zip-lines so I had to do a new play through.

How long did it take you when you started a new game?

not too long, maybe about an hour, hour 1/2. I rushed straight to those parts.

Thanks for this - You're a life saver. Only needed two more kills to get my achievement to pop and had already completed the game. Definitely beats what all of those retards are saying out there about giving up and starting a new game just to get it. :)

I've been shooting the enemies of zip lines now for an hour but the achievement is not popping. Any ideas what I might be doing wrong?

I'm having the exact same problem, I've killed more than 10 in Shanty Town post-game, and I definitely got a handful during my playthrough, but it ain't popping. Reckon it's just a bit glitchy...

Make sure you start as soon as you can because this feels glitchy. I've completed the game and did my best to shoot as much enemies off ziplines as I could. But I didn't pop. It feels like I shot lots more than 10 off those ziplines. After I completed the game hardly any enemies spawned and when they did they didn't use the ziplines.

So I had to start a new game. Takes you a while to get to back to a part where there are enemies on ziplines. :(

I'm guessing this is glitchy as some of you have mentioned. I was pretty sure I killed a lot more than 10 before beating the game, but figured maybe I just missed it due to shooting them too early or something.

I've completed the game and went to Shanty Town and there are two Solarii that spawn right above a zipline. I've shot them off the zipline 40 times and the achievement hasn't popped.

So I thought maybe CD just didn't clarify the achievement requirements in the description and maybe we actually have to kill the enemies before they hit the ground. I've done that 17 times now and the achievement hasn't popped.

I also make sure they're about halfway down the zipline sto ensure I don't shoot them early. No popage.

There are only two explanations I have for this:

1. The achievement is glitched.
2. Perhaps killing the same two guys that respawn in the same place still only counts as two since it's technically the same enemies.

I seriously doubt it's #2 because I was pretty sure I got a lot more than 10 during the campaign and I also doubt the same two respawning enemies only count as two zipline kills if you kill them once they respawn. I feel that's stretching it when looking for an explanation as to why this is happening, but I cannot rule it out. I suppose another explanation would be that perhaps these two enemies are glitched and don't count as zipline kills, but that would still fall under the glitched category, it's just more specific.

Good luck to everyone trying for the achievement. I HIGHLY recommend you do ALL your achievements where you have to kill a certain amount of enemies BEFORE you complete the game. Also, change save slots at the Fast Travel Camp where you get the "Point of No Return" message. That way you can just load up that save after you've completed the game and fast travel to areas you prefer and it won't count as completing the game. This is definitely a headache...

I missed the opportunity at the base exterior. But then, the walkthrough on this site says that the enemy who rope down to the chasm monastery hall also count. At least the sound effect is the same :). I killed 6 of them on the rope and then 7 enemys at the dynamite fight in Shanty Town. Makes 13 in total but no achievement. I think it really has to be a zip line. So I have 7 now and need 3 more but I heard there will be more opportunities later on. An advice for the dynamite fight in Shanty Town: Do NOT kill the guy at the alarm or the guys just shooting at you from far away. Let the alarm make sound, more waves of enemies will come like this and more enemies will use the zip line to get to you before they retreat! As stated, I got 7 kills like this!

@the dauntless - I've cleaned up NeXuS23's comment in my solution for you if that's what you're talking about. If it's about my section then I've clearly stated where you can do this :)

1. Spot: In Shanty Town on Top of the Tower, just before the Scene where Grim dies
2. Spot: After Transport Gondola and just after using the Zip Line down from the Tower there

Also its a good Idea to switch over to a new Save Slot before those Spots, so that you can restart there till you have memorized the Pattern.

Anyone know if this is still obtainable after completing the story? I have finished the story and I'm having trouble finding any enemies near zip lines. i hope I don't have to restart the game.

@EbonHawk01 - I found this with the rope pull stuff. Enemies have become so armoured I can't do it anymore.

The zip line stuff is harder I think. Post game most enemies are just around around in pairs and I've yet to see anyone up high. They always seem to be on the ground :(

This has the versus icon? Can it be obtained in MP?

There is definitely something wrong with this achievement. I was paying attention since the beginning and I'm sure I had around 7-8 by the end of the game. I have now completed the game and managed to get 4 kills post-game by luring enemies into ropes (in South Shantytown and in the upper village area) and I didn't get it. I'm guessing you have to just shoot them off the line and not actually kill them? That could be a reason why some kills don't seem to count. I'll try later to see if the enemies respawn in the areas where I got the kills post game.

Im having trouble completing this after completing the game. Any good spots ?

Ugh... the two shooting people off ziplines achievements are the hardest and most annoying in the game aside from level 60 MP. Its my last SP achievement I still need to get... and I TRIED to get it in the key spots, no dice. Now after the story, I have no hope in hell. :(

Just completed using the rifle exclusively.

@Ryozenzuzex - no idea how you pulled this one off, but after a while I get absolutely no enemy respawns! No matter where I go there are absolutely no enemies in the game :-(

im getting same thing as scary there are no enemies left anywhere, I have tried every location and nothing.

@Ryozenzuzex: Thank you! It took me a while to find the point to shoot my zip line to, but after that it worked perfectly!

THIS IS MISSABLE! Please Someone put the icon on the achievement description.. damn now I need to start a new playthrough

@ Ryozenzuzex Totally works, enemies would never spawn at night for me only daylight, another playthrough not needed would have been easier to do it the other way of course

a good tip for doing it during the first Shantytown fight in the campaign: don't kill any of the guys tossing dynamite at you. as long as they stay alive, then people will use the ziplines.

No enemies left for me, any ideas?

No enemies left for me too, any ideas?

@Ryozenzuzex: I was using the Shantytown spot and attempting this over and over after completing the game. It was only after reading your post about going for headshots that I finally got this achievement to pop. I hit 2 more guys with headshots (after literally piling up bodies on previous occasions) and it worked! You CAN get this after completing the game! Thanks so much for posting this.

@Ryozenzuzex / Streak Leader Your comments regarding head shots were a huge help! Like others have said was accumulating a silly body count at the bottom of the tower in Shantytown...two head shots later and *kaplink*! Thanks!

Want to add that I also needed head shots. Put about 30 down and only after going for head shots did it unlock.

Agree with obake25. I have the feeling that the counter is broke or like in multiplayer you have to use the bow.
I have shot down way more than 15 enemies down from the zipline using guns except for the bow. Since I have to play the campaign again in order to get "chatterbox" I guess I will go for this achievements again.

I just got this last night, after the main story. I found a spot that seems to be an easy farm, but enemy spawns are pretty random so bear with me. If you enter from the Shanty Town crashed helicopter base camp and look out over the shacks, you'll see a path along the roofs that runs to the right and leads up to a tall tower. As a point of reference, the top of this tower had one of the warning sirens that needs to be dismantled for the Shanty Town challenge. When I ascended, I heard guards at the top talking, and they noticed me as soon as I got to the top. I immediately zip-lined down, turned and waited for them to follow (when you reach the bottom of this zip-line, you can hide behind the shack it is connected to, then touch L3 to switch your view to help stay behind cover). When you kill them both, circle back towards the base camp (and you can stop here to force a save point) and then make your way back up to the top of the tower again. The enemies have already respawned, and you can repeat ad nauseam.

Some things to note: enemies may also spawn below and behind you when you are waiting for the two guys to zip-line down after you, so be sure not to get shot in the back. I came to Shanty Town during the daylight, although I don't know if there are different times of the day or if it effects enemy spawns. I shot many enemies and they would fall and die when they hit the ground, but the achievement didn't pop. I got the achievement after lining up head shots with the rifle and killing the enemies while they were still on the line (you can tell by when you get your XP--are they on the line or did they just hit the ground?) If you are having trouble, try to recreate those conditions by fast travelling until the enemies spawn, and take the time to line up a killer shot rather than letting the fall do them in. It is easy to zoom with the rifle, hover near the the rope, and wait until the enemy slides into position.

I am eager to see if anyone can confirm if time of day matters/what random enemy spawns occur/if the achievement can pop just by knocking them off the zip-line.