Psychological Warfare - The Kharaa Way
The way Kharaa win.Marines have weaknesses, and that is their teamwork design: They have one overseeing commander, and he is generally only in one place at a time. Marines themselves are weak if alone, and even numbers of aliens will generally win against an even number of marines (in most cases).
The real key to the Kharaa is psychological warfare. CONSTANTLY attack, especially in the early game.
* Distract the Commander - Wounding marines is often worse than killing them. Then they run around yelling "medpack" which distracts the commander and causes them to use 2-4 resources per marine. Killing a LMG marine will simply respawn, not causing the commander any resources or time. But wounding them, such as with a few lerk spikes or fade acid rockets, is a great way to distract and cause trouble.
* Attack Resource sites and Turret Factories - There is often a gap in the turret defenses, and a single skulk can get in and do some damage to a resource tower or a turret factory. So do suicide runs. If it takes 4 runs to kill a turret factory - DO IT. Once the factory goes down, so does all the turrets, the resource node, and the time and energy the marines spent putting them up. It deprives them of resources and forces them to waste more to get the same thing back. And only ONE skulk is needed to do this in most cases.
* Distract the Marines - 2 fades and a lerk can distract the marines in the mid-game by attacking a hive location or resource site. The commander and marines usually re-route to this, expend resources, time, energy, and medpacks to do it. Meanwhile the other resource sites and strategic places are being attacked by the rest of the team.
* Harass their Main Base - even a single lerk doing umbra and spiking from a vent into the marine main base can tie up 3-4 marines, PLUS the commander. The marines just don't know to ignore the lerk. If you can get a third of their team occupied with one man, you have struck a mighty blow. Even if they kill you, they'll likely throw up added defenses to prevent your return. This too takes time and resources. Any men you wounded will need medpacks. Marines often defend their base fiercely and will pile up ther eif even one or tow aliens start attacking it. Use this to distract them from your real target - a fortified hive or their now weakly defended or completely undefended resource towers.
The primary key here is TIME. The Kharaa have time on their sides. With 2-3 gorges building structures, stuff can go up faster than the mariens can put up stuff, and they don't require a central commander to do it. If you distract the marines at their main base while your gorges throw up that second hive, you have taken a great step toward victory. If you harass their resource sites every step of the way, they aren't attacking your gorges or securing hives very well.
The second key is to SPLIT UP THE MARINES. Attack several locations at once, even if it is just one skulk - he's cheap, expendible, and if he occupies 2 marines in the process, he has struck a deadlier blow than killing those 2 marines. Marines are nasty and devastating if they all move together quickly and sweep across a map in a wave of destruction. They are far less nasty if they split up into smaller teams, or get hung up defending stuff they shouldn't. They are de-fanged when their commander is distracted by trivial things, like lmg marines needing medpacks and ammo.
It's all psychological. If the marines see damage they usually run to stop it. What they really need to do is move as a focused group. If you can prevent them from doing that, you are winning the war - regardless of whether or not you die. That is a critical point. If you don't kill any marines, but you cause them to waste a lot of ammo and run around chasing you, then they have fallen into your trap. The more you distract them from their goal, the more your own goals are furthered.
Harassment is a critical weapon of the Kharaa. They are built for psychological guerrilla warfare, so use it. Lure them to useless places. Distract them from your hives. Get them to focus on places your gorges arent. And if you die? So what? You'll die, which means gorges get more resources anyway. If you do some damage, even if it is a little, keep at it. The damage will add up, and it can strike a critical blow if the enemy doesn't fix it.
To those marines reading, learn from this and don't fall into Kharaa psychological trappings. Stick to your objectives and complete them, making the Kharaa come to you in order to stop them. Don't let them lure you away. This will be your doom.