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Alien Swarm
Co-operative multiplayer game and complete code base available for free.
What players say
Steam review score and the most-helpful voices, which may include critical ones. Data as of 2026-05-20.
What reviewers agree on
56 of the 95 reviews raise this.
“Very fun game for the first playthrough, however very short with just 1 campaign available. Still would recommend to play with friends or randos online”
24 of the 95 reviews raise this.
“This is by far the most compatible game I have ever found on steam. (and of course its made by valve) If I want to play this game with one of my friends and they have a computer, they can play alien swarm with me. I…”
“Very fun game for the first playthrough, however very short with just 1 campaign available. Still would recommend to play with friends or randos online”
“This game is amazing. It’s a lot of fun and incredibly easy to pick up and play. The controls are simple and responsive, and it runs perfectly even on my “potato” of a gaming laptop. It was especially fun playing with…”
7 of the 95 reviews raise this.
“It's great, it's also free. Try it.”
“4 Player Campaign Co-op Classes Players are able to choose from, with the addition of Customizable Loadouts Unlockable Weapons, Including Shotguns, Chainsaws, and Flamethrowers In-game map you can draw and plan out…”
“👽🔫 Alien Swarm Review 🔫👽 🕹 Length: 4–6 hours (campaign) | More with replaying higher difficulties 💰 Price vs. Content: Good value, especially considering it’s free ⚙ Optimization: Excellent; lightweight and runs…”
6 of the 95 reviews raise this.
“This is by far the most compatible game I have ever found on steam. (and of course its made by valve) If I want to play this game with one of my friends and they have a computer, they can play alien swarm with me. I…”
“This game is amazing. It’s a lot of fun and incredibly easy to pick up and play. The controls are simple and responsive, and it runs perfectly even on my “potato” of a gaming laptop. It was especially fun playing with…”
“👽🔫 Alien Swarm Review 🔫👽 🕹 Length: 4–6 hours (campaign) | More with replaying higher difficulties 💰 Price vs. Content: Good value, especially considering it’s free ⚙ Optimization: Excellent; lightweight and runs…”
6 of the 95 reviews raise this.
“Sqaud tactics very important and get friends to play especially when playing brutal, most important have fun!!!”
“👽🔫 Alien Swarm Review 🔫👽 🕹 Length: 4–6 hours (campaign) | More with replaying higher difficulties 💰 Price vs. Content: Good value, especially considering it’s free ⚙ Optimization: Excellent; lightweight and runs…”
“Only played for the team fortress hat but i liked this game. hard as ♥♥♥♥.”
6 of the 95 reviews raise this · 6 of them still recommend the game.
“Very fun game for the first playthrough, however very short with just 1 campaign available. Still would recommend to play with friends or randos online”
“The Team Fortress 2 hat doesn't look that good if that's all you're here for. Good game; would recommend checking out the sequal and playing that for what little content this one offers but still good on it's own.”
“👽🔫 Alien Swarm Review 🔫👽 🕹 Length: 4–6 hours (campaign) | More with replaying higher difficulties 💰 Price vs. Content: Good value, especially considering it’s free ⚙ Optimization: Excellent; lightweight and runs…”
4 of the 95 reviews raise this · 4 of them still recommend the game.
4 of the 95 reviews raise this · 1 of them still recommend the game.
“Review after 100% ♡♡♡ The hardest Valvefanboys I know think this game is trash. Alien Swarm: Reactive Drop the sequel to this game is a better game. A nothing game without controller support. Error on startup, need to…”
“We had a lot of fun on this. The controls feel good and although it is a railed instance style game. It's multiplayer and it has cool diverse roles. For example the hacker has to play a hacking minigame while a heavy…”
“I Don't Really Get What Im Doing With This, It's The Only Valve Game That's Confusing To Get Your Head Around. Also, Source Just Doesn't Feel Right As A Top Down Co Op Shooter. I'll Go Into Detail About Other Issues. 1.…”
3 of the 95 reviews raise this · 3 of them still recommend the game.
3 of the 95 reviews raise this · 2 of them still recommend the game.
“amazing game, old, crappy quality, but fun”
“I Don't Really Get What Im Doing With This, It's The Only Valve Game That's Confusing To Get Your Head Around. Also, Source Just Doesn't Feel Right As A Top Down Co Op Shooter. I'll Go Into Detail About Other Issues. 1.…”
Counted across 95 English reviews, sampled to match this game's 94.9% positive rating · as of 2026-05-20
“▬▬ | Graphics | ▬▬ 🔳 You forget what reality is 🔳 Beautiful 🔳 Stylistic ☑️ Good 🔳 Decent 🔳 Bad 🔳 Don‘t look too long at it 🔳 Other: ▬▬ | Gameplay | ▬▬ ☑️ Very good 🔳️ Good 🔳 It‘s just gameplay 🔳 Mehh 🔳 Watch paint dry instead 🔳 Just don't 🔳 Other: ▬▬ | Audio | ▬▬ 🔳 Eargasm ☑️…”
— a player, Steam review · 24 hrs played“I thought its some kind of a free indie mobile game but then I just realized its made by ♥♥♥♥♥♥♥ Valve😭 after finishing this peak and looking at the credits. No wonder that the game has actual good mechanics and it actually feels like it have a soul. Not sure how good it is by…”
— a player, Steam review · 3 hrs played“classic, but still running. almost 200 hours in this game, and i still enjoy it”
— a player, Steam review · 200 hrs playedPlayer activity
Monthly average concurrent players. Live count fetched 2026-07-11 11:37 UTC · history via SteamCharts.
Achievement stats
Global completion rates across all Steam players — a data view of how far people actually get. Source: Steam official stats · as of 2026-07-25.
Price tracking
US-region pricing (USD), sampled twice daily by our own tracker since 2026-07-11. Steam prices vary by region — always confirm your local price on Steam.
Latest official news
Developer announcements via the Steam news API — links go to the original posts. More across all games on the news hub.
Alien Swarm update released
Fixes and Updates Security fixes to client/server file transfers Fixed "Out of thread ids" error when launching Alien Swarm on a computer with 32 or more logical processors Updated localization files
Games like Alien Swarm
From our knowledge graph — ranked by shared traits, not a black box. Each card says why it's here.
Halo: Spartan Assault
73.9% · 2,687 reviews
shares Aliens, Third Person Shooter, Top Down Shooter, Co Op
Halo: Spartan Strike
76.2% · 875 reviews
shares Aliens, Third Person Shooter, Top Down Shooter, Co Op
Thunder Tier One
71.0% · 2,164 reviews
shares Moddable, Team Based, Top Down Shooter, Online Co Op
Predecessor
72.2% · 11,946 reviews
shares Team Based, Third Person Shooter, Online Co Op, Free To Play
Alien Swarm: Reactive Drop
94.1% · 6,656 reviews
shares Class Based, Moddable, Aliens, Third Person Shooter
Aliens: Fireteam Elite
81.5% · 17,267 reviews
shares Aliens, Third Person Shooter, Online Co Op, PvE
ORION: Prelude
75.9% · 16,930 reviews
shares Team Based, Third Person Shooter, Online Co Op, Co Op
Ultimate Zombie Defense
83.2% · 1,205 reviews
shares Team Based, Top Down Shooter, Online Co Op, Co Op
Screenshots
Official Steam store screenshots — click any shot to enlarge.
Facts & details
From the Steam store record, snapshot 2026-05-20.
| Genres | Action, Free To Play |
| Player tags | Free to Play · Co-op · Action · Multiplayer · Online Co-Op · Aliens · Shooter · Sci-fi · Top-Down · Top-Down Shooter · Survival · PvE (SteamSpy community voting) |
| Features | Single-player · Multi-player · Co-op · Steam Achievements · Captions available · Camera Comfort · Color Alternatives · Custom Volume Controls |
| Languages | English |
| Achievements | 66 |
| Estimated owners | 2,000,000 – 5,000,000 (SteamSpy) |
| Official site | http://www.alienswarm.com |
Minimum system requirements (PC)
Minimum: OS *: Windows® 7 / Vista / Vista64 / XP Processor: Pentium 4 3.0GHz Memory: 1 GB for XP / 2GB for Vista Graphics: DirectX 9 compatible video card with 128 MB, Shader model 2.0. ATI X800, NVidia 6600 or better Hard Drive: At least 2.5 GB of free space Sound: DirectX 9.0c compatible sound card