General things to know

• Dead Air is back to the No Mercy method of weapon distribution. In other words, completely at random! Well, not completely. Weapons appear on certain tables or in certain places, but it's almost always at random. The two places where they are always present are the level 4 and 5 safehouse and the finale house.
  
• Dead Air is lots of confined spaces interspersed with huge, wide open spaces. Use your Molotovs in confined areas, and save your pipe bombs for the huge areas.
  
• Infected will hide behind fences that you can't move around, which are present just about everywhere in Dead Air. Be careful. They also jump over these fences when the Horde is triggered. Fun times!
  
• Dead air marks the return of car alarms! It also has metal detectors as well. Make sure not to run through them, or the alarm will set off a Horde.
  

Stage 1: The Greenhouse

Walkthrough: Yet another campaign filled with bloodthirsty cannibals. Time to hoof it to the airport! This level is pretty simple. You start off in a greenhouse and must make your way across a few roofs into an apartment complex. Go through the complex until you reach street level, where you run across the street and enter the safehouse.

Horde Choke Points

• In any of the rooms in the buildings. Each room is small, has only a few entrances, and usually have doors, which slow down infected.
  

Tips and Tricks

• There is a car on the street immediately before the safehouse. Don't hit it, unless you enjoy having a Horde tear you a new one!
  
• Akimbo pistols are normally in one of the bedrooms inside the building right before the safehouse. They are valuable, so make sure to find them
  
• Punching Infected off the roof is a great way to conserve ammo. It's also hilarious!
  
• A pipe bomb is a great way to thin out the Infected in the street right before the safehouse. Just make sure that the explosion doesn't set off the car alarm.
  
• Smokers can - and will - pull you off a roof to your death. If you are being dragged, try and get the smoker before he starts constricting you.
  

Stage 2: The Crane

Walkthrough: This level is much like the last: a mixture of buildings and roofs until the end. Make your way out of the saferoom, over the fence, and up the fire escape. Head up through the building until you see the crane. Triggering it creates a Horde, so be careful. After making your way across the rest of the roofs, you jump into a building, make your way to ground level, and head into a safehouse in a storage area.

Horde Choke Points

• In any corridor or room inside the buildings. I'm pretty sure I don't need to spell out why anymore.
  
• In the stairwell of the office building. the Horde only comes from one floor, normally, making it extremely easy to bottleneck them into a slaughter zone. However, Infected that didn't spawn as a part of the Horde will still chase you down, so one person guarding the flank should be enough.
  

Tips and Tricks

• Surprisingly, the crane area has little in the way of good chokepoints. However, judicious use of Molotovs and gas cans can make surviving it a lot easier. Simply cause the fire immediately outside the fence and wait for the Horde to burn to death!
  
• The Tank spawns next to the crane most of the time, but can also be found inside one of the buildings. If he does spawn in a building, you may as well restart the level; he will kill your entire team fairly easily.
• Interestingly enough, the Witch often spawns in one of the cubicles, which makes her extremely hard to trigger. Just keep running through the office and ignore the crying.
• The cubicles are great makeshift defensive positions if you can't make it to one of the offices in case of Horde. The Infected have troubles getting into them, and the only entrance is very narrow.
  
• The bedrooms and offices inside the buildings you trek through are chock-full of supplies, ranging from grenades to ammo. However, in case of Horde, they also have lots of Infected pour from them.
  

Stage 3: The Construction Site

Walkthrough: Finally, a change of pace! Start off by leaving the safehouse and going through the alley out into the construction site. In order to continue, you must shoot the gas cans by the barricade, triggering a Horde. After you fight your way through, run through the next alley until you come out near a maze of power transformers. Make your way through into the garage area, which spits you out into the parking lot of the airport. Move through the lot and up the parking garage until you reach the next safehouse!

Horde Choke Points

• Right next to the exploding barricade, up on the stairs right next to the building. Special Infected have lots of trouble getting past the railing, as do regular infected. It's also easy to just throw two Molotovs or gas cans into the alleyway and trigger them to burn the infected.
  
• In the maze of transformers. The Infected have to move through narrow killzones, but more importantly, Tanks have trouble moving through the maze. Use this to lead a Tank around while you blast him to pieces.
  
• In the parking garage stairwell and, by extension, the garage skybridge. Narrow area, limited moving area, you get the idea.
  

Tips and Tricks

• This level is so long that it is not unusual to end up fighting two Tanks or seeing two Witches. Tanks usually spawn in the construction site or near the transformers, and Witches normally spawn in the parking lot or parking garage. There are exceptions to every rule, but these seem to be the most common places.
  
• Pipe bomb the parking lot. No ifs, whens, or maybes. Dealing with all the infected there takes way too much time, which increases the likelihood of a Horde.
  
• The parking garage has a lot of extra goodies if you fully explore each level, ranging from grenades to pain pills. If you are hurt bad, ignore it, but otherwise, have a ball finding all the supplies.
  
• After the power transformers is the most common resupply spot. It has pills, ammo, and grenades, as well as advanced weapons from time to time.