The main baddies in Dead Space 2 are an alien recombinant virus called Necromorphs. For the necro-newbs out there, Necromorphs reproduce by reanimating dead flesh, acting as a virus by mutating bodies into different types of Necromorphs. They are definitely a narcissistic bunch of aliens as their only goal is to simply make more of themselves, but they'll scare the poop out of you while they do it.
While playing Dead Space 2 you'll encounter many of the same enemies you met on the Ishimura in the original Dead Space, but DS2 wouldn't be a very good sequel if there weren't a plethora of new Necromorphs hell-bent on killing you. The best thing about Necromorphs is that while they're like snowflakes, unique in their own special way, they have weaknesses as well. Like heat. You know, because heat melts snowflakes. Luckily, there's also a flamethrower in DS2.
Infectors are winged Necromorphs, they use their wings to hover and to hold down their victims. As their name suggests they enjoy spreading the necromorph virus and infecting dead bodies. The good news is that they tend to avoid living flesh unless they detect that a threat, but the bad news is that they make more Necromorphs out of dead tissue. Word to the wise: shoot off the mosquito-like proboscis to kill them.
In order to survive you're going to want to become familiar with all the Necromorphs, so read on for our guide to the creepy, virus-borne baddies that are these walking dead mutations.
Slashers might be the first Necromorph you come across. They have razor sharp scyth-like arms that come in handy when ripping through human flesh, or any kind of flesh for that matter. With the kinesis module I highly suggest sending a few metal rods through their chests. With the stasis module, put them in pause and take off their limbs shot by shot. Slashers are fast; no matter your weapon of choice make sure to take out their arms first, because even without the legs they'll keep crawling after you. The good news: you can uses those arms as powerful weapons via kinesis.
Cysts look like gigantic, infected pimples, and are activated when you're close to them. Once you're within proximity a sack will open and send out short tentacles, and if you get much closer it will shoot an explosive pod out at you. If the sack is on the floor, shoot it from a distance (or kinesis an object at it) or get close enough to activate it and then haul ass out of there, as the pod it shoots up in the air will plummet down and kill it. But if it's on a wall or ceiling, you may have to take it out with ammunition as the explosion might not reach wherever it's anchored.
Instead of legs Leapers have a long tail with a stinger at the end. They can crawl up walls and across ceilings, which means you could come across one at the most inopportune times. Plus, they move very quickly so you'll have to nail them with stasis quickly to keep them from slithering. Leapers and Infectors are both vulnerable to stomps when they're on the ground, so keep your boots handy. Watch out for these guys in zero gravity, because their wall-crawling abilities make it possible to drop in from anywhere.
As you may have guessed. the Pregnants have a sack belly. Don't shoot it in the belly unless you want to release the Swarm (Hint: you don't) because then you'll have to deal with the Swarm as well as a crawling Pregnant. It's probably best to just shop off their head, which is best done by putting them in stasis and removing their blades first.
If you're only dealing with a two or three Packs a few melee attacks should take care of them. But if there are a lot of them, or If they begin surrounding you, kill them, kill them fast. A good tactic for this is to run away in a straight line so they'll follow you, then quickly stasis the lead Pack, then hit him with a Javelin shot. Switch to alt-fire immediately, and you should chain-fry them with lightning. The Line Gun also works well here, chopping them up like weeds, or even fire. Yeah, fire is definitely good in this situation. You don't want these little guys swarming you.
If you see a Puker, keep your distance. This is generally a good rule for anything or anyone who fancies projectile vomiting. Pukers have two attacks, the standard puke attack works from a few a feet away and does damage to you, while the second is sticky will slow you down tremendously. Luckily, they telegraph this attack with a big inhale, so if you're keeping watch you're probably notice it. Be careful though, the liquid it spurts out upon death can hurt you too. Lovely. So keep a close enough distance to keep it from launching the slow attack, put it in stasis and then kill it while making sure you aren't too close.
The Swam are very diminutive in size, so one or two might not be a problem. But as the name suggests there tend to be many of them. To defeat them use area attacks with weapons like the flamethrower, or the alt-attacks provided by the Pulse Rifle, Line Gun, Contact Beam, or Javelin Gun. If there's only a couple of these little things around, just let them crawl up your body and then pound the action button to squash them.
The Spitter is a type of Slasher and can be killed using the same methods. Unlike Slashers they also have a projectile attack that you can send hurtling back at their faces with kinesis. Otherwise, treat them like standard Slashers and chop off those sharp limbs.
Lurkers are infected babies who has three tentacles that emerge from their backs which are used for hurling barbs at you. Their bodies can handle a lot of damage so don't waste your bullets shooting them. Instead, focus on dismembering it, tentacle by tentacle. Line guns and plasma cutters work best for this, and keep a sharp eye out for them in zero-g as they can adhere to any surface. They'll also reposition themselves to get a better shot at you, so take them out early.
These are humanoids which look like they've been glued onto walls, and have multiple tentacles emerging from their middles. Guardians can kill you with one hit, which means you can't simply run past them. Plus it will shoot pods out of its stomach which will skitter across the ground and launch projectiles at you from a single tentacle. Ignore the pods if you can and take out all of the tentacles to kill it. Explosive canisters work well with kinesis, or stasis them and blast the tentacles one by one so they can't retract.
These guys look like they're lugging a gigantic, glowing, yellow sack, which will explode if you shoot it. Unfortunately, they are often at close quarters, and the resulting explosion will result in immense injuries for you. If it's far away, pop that sack with a projectile weapon. But if it's nearby, stasis it and run, or just run. Shooting that sack at close range is a very, very bad idea.
These are mutated dead babies who walk upside down on their hands and feet with swollen bellies full of explosive goo. Just about every part of the Crawler's body can trigger an explosion so keep a safe distance. If you can, lure it close to other enemies before blowing it up, or grab it with kinesis then toss it into another enemy. Two Necromorphs with one stone.
When attacked Dividers break into smaller parts, and then each of those parts will attack you. Use stasis while these parts are close together to kill them. If they manage to separate, get your back up against a wall as fast as possible so you can see where they are coming from. You'll often hear these things before you see them, so keep your ears open for their eerie groans and then don't let them divide.
Nests are immense Necromorphs with three waving arms that have yellow vulnerable spots on them, but they will also hurl projectiles out at you. Nests can be killed with a single shot from the Line Gun's alt-fire, but if you aren't carrying one or are out of ammo for it, then you'll have to take it down arm by arm while avoiding the projectiles. It will stop moving for a bit after releasing projectiles, so take your time and watch your air meter as you encounter these guys in space where breathing air is in extremely short supply.
Brutes might be intimidating but as long as you remember their shoulders and knees are their weak spots you'll be okay. You'll also want plenty of stasis with these guys, and they'll track you pretty well so don't think you can just walk up to them and fire away while they're frozen. They have a nasty projectile attack that shoots out of its belly, and with practice you catch that via kinesis and lob it back at them. Handy if you're low on ammo.
You'll encounter other types of Necromorphs throughout the game, and as a general rule any glowing body parts are indicators of weakness. Stasis won't work against all of them, but it's always worth trying against the larger and more powerful Necromorphs, since you won't last against most of their attacks for more than a couple of hits.