Generally favorable reviews - based on 11 Critics

Critic score distribution:
  1. Positive: 8 out of 11
  2. Negative: 0 out of 11
  1. Minor quibbles aside, this is a must-play game for action gamers, especially those who enjoy playing cooperatively online.
  2. Totally free, and totally worth your time. [Oct 2010, p.65]
  3. Left 4 Dead minus the Zombies, plus a truckload of skittering aliens. Pure brilliance, and free to boot? Valve knows how to make their customers happy. Get to downloading it, stat!
  4. Addictive. Fun. Community driven. Free. Where can it go wrong?
  5. Simply put, anyone with a capable PC should download this and try it.
  6. Download Alien Swarm. Do it, it's an order. It's one of the best freeware games of all times. It's fun, addictive and has great growth possibilities considering how actively the Steam community is already working on it. Thanks for the gift Valve, we love it.
  7. Left 4 Dead top down! Alien Swarm is fast-paced, alien-filled fun that demands cooperative gaming and delivers cleverly directed missions that stay challenging from beginning to the end. The upgrade systems serves as a motivator and the match making is quite good. Physics, sound and lighting convey a spooky atmosphere. Although there is only one campaign at release, Alien Swarm delivers more fun than most full-price games.
  8. Despite the issues of repetition and somewhat contrary design choices, Alien Swarm is an enjoyable shooter at an absolute steal of a non-price.
  9. Alien Swarm is a free game and has been updated regularly to try to iron out the remaining bugs (excuse the pun). All things considered, as it stands the game is a little disappointing and falls short of its true potential.
  10. At least Alien Swarm doesn't try to be anything other than what it is. It's an online action shooter with plenty of things to shoot at.
  11. Not a very interesting 2D shooter, but fans are likely to create something far more exciting from it.
User Score

Generally favorable reviews- based on 394 Ratings

User score distribution:
  1. Positive: 61 out of 71
  2. Negative: 2 out of 71
  1. Aug 20, 2010
    This game, while small, is a great game from Valve that's like a top down version of Left4Dead except with alien bugs. It runs on the Source engine and enables people to make their own maps which is a plus. I like how weapons are unlockable but the default weapons still can stand a good chance against enemies on higher difficulties. Overall, it's free and I can't think of a reason not to buy it! Valve sure knows how to cater it's fans with free little gems like this game. Full Review »
  2. Aug 27, 2010
    Raw, free awesome. Make sure to play with people you are at least a little before going on modes harder than normal. Highest difficulty is where to go if you want a challenge and actual tactics. Also, expect to die on the harder modes at least as you first start out when you get better it becomes epic. Full Review »
  3. Nov 10, 2011
    "Alien Swarm" is a suprisingly fun 4 player co-op game with tons of stuff to do. You will have a good time upgrading and choosing characters and weapons to use for your battle with alien bugs. Oh and btw...It's Free. Full Review »