The Orange Box

I did this during the bridge battle towards the end of the "Follow Freeman" chapter, just before you come to fight the Striders for the first time (and just after a gunship battle, if we're being thorough). The enemies are clustered into a small room at the opposite end of the bridge, so one good shot with your energy ball (note for the ignorant, which I once was among: the energy ball is the alternate fire button on your pulse rifle) into this crowded area and you can count yourself unlucky if it doesn't bounce around and take out 5 people; there are about a dozen combine soldiers come through that room in total, so lots of achievement fodder. If not, reload your game (you DID save it beforehand, right?) and try again, it shouldn't take too much effort in this location.

A great place to do this is in the Our Benefactor chapter. After you get your super charged gravity gun you'll eventually come go up a small lift then go thru a passage on the right (don't forget to recharge your suit in the passage). When you come round the corner, there will be many enemies coming after you in groups of 3 or 4. This is a great spot to get both the Conservationist and Atomizer achievements.

Best place to get this is in the citadel. You will find energy balls floating around all over the place. Simply pull one in with the Gravity gun, kill a guard, then suck it back it, when you come upon another kill him, rinse and repeat five times. Easier to do in confined areas as its easier to suck the energy ball back in with the Gravity Gun.

All the solutions regarding doing this achievement on Our Benefactor in the citadel are correct, I'd just like to elaborate on the way the achievement works and how I found it easiest to complete.

First off, you will want to turn on invincibility for this achievement method. Entering codes DOES NOT forbid you from saving/earning achievements. If you really wanted to, you could play the whole game with invincibility on. You turn on invincibility by entering this code DURING GAMEPLAY: Left Bumper, Up, Right Bumper, Up, Left Bumper, Left Bumper, Up, Right Bumper, Right Bumper, Up. The game doesn't tell you that the code has been activated, so test it out first before doing this method otherwise you will die.

Once you go through the narrow hallway with the recharge station (On Our Benefactor after going up the lift with the Blue Gravity Gun), you'll be in a small room cut off due to a barrier. First off, disable the barrier by taking the energy ball from the machine against the left wall in the corner. This will deactivate the barrier in front of you: now you are free to roam the room. Guards will start to come into the room from the two massive hallways in front of you and to the right of you in packs of usually 4. What you want to do is kill just enough guards to spawn another pack, so you'll have 5 or 6 guards at once for your disposal. Once you have 5 guards, you're ready to go for the achievement using the method I used. What you will want to do is put your back to the large machine flowing multiple energy balls and position the guards in front of the machine that held the one energy ball that held the barrier intact but you do NOT want the guards to be in a single file line. Once you have one that is lined up with the original barrier machine, turn around fast and grab an energy ball from the machine with multiple balls. Then turn back around and shoot it at the guard in front of the original barrier machine. It should kill the guard and then instead of having to catch the ball again before it bounces everywhere, it will get caught in the original barrier machine, thus making it very easy to obtain again. Now just grab your energy ball out of the original machine and repeat with the other 4 guards.

Please note that if you kill more than one guard with the ball at the same time it will not count as 2 but only 1, so make sure you are killing them off one by one.

This method may seem a bit overcomplicated but it's actually very simple and it makes this achievement much easier in my opinion. The fact that you don't have to catch the ball again or rely on ricochet makes this SO much easier. Out of all of the Half Life 2 achievements, I'd say this one was one of the more challenging so I hope this helped.

I got this totally unexpectedly and found a neat little trick for it.....if you shoot the enemy that has those bugs attached to him that detach from him and attack you once you kill him (i don't know his name), you automatically get it because each enemy attached to him counts as one.

Use the level "Our Benefactor".

Use the area just past the corridor. This is where you pull out the energy ball to take down the blue screen.

The easiest way to do this is to position the soldiers between yourself and the "Single Ball" energy machine.

Then () to get the ball and shoot it at a soldier (). He'll die and the ball goes back into the machine. Do this 5 times ... simples.

Putting the invincibilty code in helps also. (Just press during gameplay)
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The easiest place (in my opinion) to get this achievement is right after you get:



When you and Alyx are going into a long hallway, and the lights go out and several combine soldiers ambush you and throw red flares. From the autosave just before the doors to that hallway, pull out your pulse rifle (obviously you'll need at least one energy ball ammo in it), and simply open the doors, sprint straight to nearly the end of the hallway, position a shot towards a bunch of soldiers as they vaguely line up, and hope for the best. Shouldn't take more than a few attempts (especially if you have the invincibility cheat activated - , , , , , , , , , ). I got it on my second attempt.

Good luck!