Hey, I don't post here very often but I made a guide and deicided to share it. Most, if not all, applies to you guys too, because I originally posted this on the NS fourms. Hope you guys like it!
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Before I begin, I would like to say thank you for reading this. It’s my first guide to doing anything, and I’m quite proud of what I’ve got so far. If you got any suggestions or comments, feel free to tell me. But before you post, consider these rules:
1. NO flaming. I absolutely hate flaming because there is usually no point. You may criticize others and disagree, but be polite about it.
2. Backup any negativity. There comes no useful discussion if you say “this is stupid” or “this guide sucks”. If you say something like that, state why you feel that way and if possible give solutions. Also, make sure you follow rule #1.
3. Don’t be afraid to post objections. If you feel that something is wrong or doesn’t really work, post it! I want this to be complete and thought through guide, so anything is welcomed. I won’t get mad at you to criticize, if anything I’ll be happier.
With that done, I’m going to say that this is going to be an ongoing project for me until I get every chamber done. My ultimate goal is to get a sticky and to have as many newcomers as possible read this guide. This is something for the new and the old alike, so I hope you enjoy it!
Part 1: The General Tips
When you drop a chamber, there are certain things to consider before you drop it. If you don’t remember these things, you will end up spending much more res ineffectively and could potentially have a less effective life. Even If you don’t read the rest of this guide,
please at least consider these questions before dropping.
Where should I drop it? Is it really worth the res there?
How should I drop it? What spot would this be the most effective?
When should I drop a chamber? The answer isn’t “when I get 10 res”
Part 2: The Offence Chamber
The offence chamber is a chamber which is a great force to be reckoned with, if placed properly. It has 1000 hit points, it deals 20 damage per hit and has a ROF of 1 spike every 2 seconds; it’s a wonder why we don’t use it more. An offence chamber, if placed correctly at the right time can easily take out a marine. Here are my tips to unlocking the full potential of an OC.
Where should I drop them?
This question is the most important question to ask, especially for an offence chamber. If you don’t answer this question, the offence chamber will most likely be a useless piece of 10 res. Here are my suggestions:
Medium Combat Area’s are the area where I find the OC is the most useful. The reason for this is because the offence chamber is relatively ineffective in high combat and low combat. In medium combat areas, there are usually small groups of marines (1 – 3) which is what the OC specializes in. More marines would spell destruction to the OC and less marines it becomes more decoration than fighting machine.
Low Combat Area’s are the areas which I wouldn’t recommend to place these things, but are still useful. Usually in low combat areas, there are few marines, which is what the OC specializes in getting rid of. Also, the aliens are usually away from these areas, so some early detection is nice.
Early detection is one of the great things about OC’s. It can be more effective than a SC because the hive sight alerts are more noticeable than the red dots on screen and that the OC isn’t a passive structure like the SC. The OC forces a marine to do two things, ignore the OC or shoot the OC back. If the marine ignores it, he will be fired upon till death or at least long enough to remove some armour. If he shoots it back (which most players do) he will stop to take cover and shoot it slowly down and an alert will be sent to the aliens showing the chamber under attack, which attracts the fades there.
Medium-small areas are the best areas to place OC’s. Medium sized rooms are good because the OC can use all of its 800 unit radius range. Because of that, it’ll land more spikes on the marines and remove more health. OC’s placed in open areas are also harder to remove because the LMG is ineffective at long range, the pistol carries a small amount of ammo and grenades don’t really reach. Smaller sized rooms make spikes harder to dodge (except at point blank range), which is a disadvantage of large rooms. That’s why medium-small are the best rooms.
Open, minimal cover areas are very effective for OC’s. Believe it or not, the marine needs the cover more than the OC because a regular marine falls to the OC easily. It’s also hard to find good OC cover in most maps anyway. Big rooms force the marine to take cover far away at the door and don’t allow the marine to run past it without taking a large amount of damage.
Near important things like rts or siege spots are also great places for OC’s. They prevent the marines from doing something important without damage or forcibly slow down the marine.
How should I drop them?
This is the question that will determine just as much as the previous question how well your OC will preform. This could be even more important than the previous question too!
Minimal grouping is something that you should keep in mind. Personally, I find that you squeeze the most out of your OC if you spread them out rather than bunch them up. The advantage of this are:
1. Marines are more likely to run in and get hurt rather than avoid it altogether.
2. It’s less deterrent to a rambo if it were spread out through the whole area rather than a huge wall of it. More marines would risk ramboing only to die.
3. If the marine shoots a grenade, it would only hit the one chamber. The other chambers won’t get hit by the splash damage. Same goes for guns, the bullets that miss won’t hit the chamber right next to it.
4. It covers a larger area, which discourages the comm from sieging and if you place 1 in each corridor, the comm
won't siege unless he's filthy rich or just plain dumb.
5. It covers a larger area, which is always a good thing

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Packs of 2 – 3 are ok. Especially with the new way the DC’s work, 2 OC’s and a DC works now. These are more effective in higher combat areas than 1 in each corner, and are pretty cost effective too.
Place them on corners! This is the absolute most effective and best piece of advice I can give for dropping OC’s. The reason for this is because it now covers a HUGE area compared to before. I cannot stress this one enough, because this one makes the OC twice as effective. This combined with 1 on each corner will still make rambos come in only to be caught between 2 OC’s and little health. Here’s an example:
(Picture is supposed to go here, but I cant post URL's until 15 posts, go to my post on the [NS forums > Natural Selection Disscussion > Kharaa Strategy > The Art Of Dropping] for the actual guide and picture included)
Now, the marine would see the first OC and pass by it and most likely pass by the second one too. By the time he meets the first green line, he can’t turn around or he is dead, so he continues ahead. He continues to meet OC’s until his death at the second green line. In this formation, he has no place to hide and no place to run either. He can shoot it down, but it will take a long time.
Place them on high ground. High ground isn’t necessary, but sure does help. On high ground the OC has a larger view (most of the time) of the surrounding area. Also, grenades and GL grenades go in an arc trajectory so it would be harder for a grenade to hit. That’s because most of the time the ceiling is too low for the grenade to reach and the grenade the marines carry explode fairly quickly. They are also harder to knife and harder to avoid. Lastly, they look more scary too

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When should I place them?
This part is kind of hard to write a guide for. This part is more up to you than anything else. Here are some questions you should pose yourself before you place an OC.
Can I afford to drop it? You want to make sure that you have enough res inflow to balance the price of the OC.
Would the OC be more valuable in this situation than a RT? If you control maybe half the map and you’re not gaining ground very quickly, it probably is worth it.
Would a DC/MC/SC be more valuable to my team? Remember that your team members are more valuable to you than an OC. An OC can only do so much, but a teammate can do so much more. If it’s a high combat area, your fellow aliens would need healing more than a measly OC. If it’s a low combat area, it would be worth it because not much fighting happens here and the OC can reduce the amount of fighting needed later on.
How easily can the marines destroy it? If all the marines have HA/HMG’s, then it will be a cake walk for them to destroy that OC. If you got no lifeforms to back up the OC, then it will again be a cake walk. But if your winning over the marines or the marines are equal to you (and don’t have HA or HMG’s), then it would be more likely to be worth it.
Would I spend my res better on being a lifeform? Maybe your fellow aliens need a lerk? A lerk can be a powerful asset, especially with the gas. Lerk is supposed to be support, not a fighter, so don’t worry about being a bad aimer (like me). Maybe you’re a good fade, because the aliens can never get enough fades. Maybe an onos, because the stomp can REALLY help your teammates get those pesky HA’s or HMG’s.
Conclusion
In conclusion, the OC is the most unused but the most useful chamber. It can make or break a game, because it can be the sole thing alerting you to a shotgun rush or the thing that stops that rambo PG from going up. It lightens the workload of the aliens, and piles it on the marines. Basically, the OC cannot and will not replace your team members, but it can supplement them and decrease the workload a heck of a lot.
Parts 3 – 5 (or 6) to come
Credits:
Chocolate: For writing this guide
Ambritenaro (spelling to be checked): For joking around about dropping chambers made me make this guide

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Alite: He didn’t do all that much, but I have NS discussions with him every once and awhile.
Tactical Gamer Server: Heh, I like playing on this server. It’s also the server on which I play on the most and originally played on and got the idea of making this guide.