Drones make up the bulk of the Swarm's numbers and "manpower". Marines can be expected to encounter several dozen of these per mission, and possibly end up killing in the region of several hundred each over the course of a campaign.
Drones are weak in terms of durability, but fast, strong, and numerous. Their four massive claws can inflict horrendous injuries on marines unlucky enough to get hit. Being swarmed by Drones (especially if you have an empty gun and no backup weapon) is a surefire way to end up dead, no matter the difficulty level. A single Drone is only a minor threat to a marine and easily dispatched with gunfire or even a melee attack.
- Countering drones is easy; make your shots count, stick together, and cover your teammates whilst they're reloading or if they're being mobbed.
- Drones move more slowly if they're electrified by the Prototype Rifle or Tesla Cannon - neither of which will slow down or harm teammates, so use this to your advantage. Stunning a mob of Drones that are trying to gang up on a squadmate can give them breathing room to backpedal, reload, use items, and so on.
- Drones on fire, such as from a Flamer will be slowed down and often stop attacking marines and stumble around on fire. Alternate 'puffs' from the flamethrower with melee attacks to make short work of swarms of drones.
- Drones are very lethal on Brutal, as a single hit by their claws can reduce the health of weaker characters (such as medics) by almost half. They're also capable of withstanding a much larger amount of damage, making basic weapons less effective against them. It is highly recommended that at least one player carry a Minigun or Autogun to deal with drone swarms.
- The drone's beta model/variant was intentionally supposed to be a recolored version of the original Alien Swarm: Infested's drone, however the Shieldbug, Mortarbug, Harvester, Parasite, and Queen did not exist in the original game, even though the appearance shares a similar style.
- The original Alien Swarm drone started off with a very early design which looks similar to that of the beta one, have 4 large arms mounted with huge razors and a tail armed with a sharp spine. The drone looked alot more tougher and buff than the new drone, being very muscular and having a strong looking husk. It was referred to as the "adult alien" for the while, along with a Buzzer, Queen and Parasite concept.
- The original UT2k4 Alien Swarm drone looked a lot different compared to the beta and recent drone, having only two claws and two arms with hands. They also used a similar skin palette to Alien Swarm: Infested's drone.
Very rarely, drones may spawn as nigh-invulnerable super drones that can absorb exceptional amounts of damage before dying. Perhaps the most efficient way to kill them is to deploy a Bullet Sentry to distract the drone. It will eventually destroy the sentry, but the sentry's explosion should also kill the drone. As an alternative one can also use a Chainsaw and run into them (playing Vegas or Jaeger).