Synergy enables you to play through the Half-Life 2 series and many other 3rd-party campaigns cooperatively with friends.
User reviews: Very Positive (2,016 reviews)
Release Date: Sep 1, 2005

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Community-Made Mod

This game requires that you own Half-Life 2.

Click here to learn more about mods on Steam.

Play Synergy

Half-Life 2 Mod

 

Recommended By Curators

"(Mod) This is a Must if you like the half-life games. All singleplayer campaigns are now multiplayer & better than ever. Black Mesa Source comming soon!"
Read the full review here.

About This Game

Synergy enables you to play through the Half-Life 2 series and many other 3rd-party campaigns cooperatively with friends.

Supported Games:

System Requirements

Windows
Mac OS X
SteamOS + Linux
    Minimum
    OS: Windows® 7 (32/64-bit)/Vista/XP
    Processor: 1.7 GHz Processor (Requires support for SSE2)
    Memory: 512MB RAM
    DirectX: DirectX® 8.1
    Hard Drive: 1 GB available space
    Sound Card: DirectX Compatible
    Network: Broadband Internet connection
    Recommended
    OS: Windows® 7 (32/64-bit)/Vista/XP
    Processor:Pentium 4 processor (3.0GHz, or better) (Requires support for SSE2)
    Memory: 1GB RAM
    DirectX: DirectX® 9
    Minimum
    OS: OS X Mountain Lion 10.8
    Processor: 1.7 GHz Processor
    Memory: 1GB RAM
    Graphics: NVIDIA GeForce 8 or higher, ATI X1600 or higher, or Intel HD 3000 or higher
    Hard Drive: 1 GB available space
    Network: Broadband Internet connection
    Minimum
    OS: Ubuntu 12.04, SteamOS
    Processor: 1.7 GHz Processor
    Memory: 1GB RAM
    Graphic Card: NVIDIA GeForce 8 or higher, ATI X1600 or higher, or Intel HD 3000 or higher
    Hard Drive: 1 GB available space
    Sound Card: OpenAL Compatible Sound Card
    Network: Broadband Internet connection
Helpful customer reviews
124 of 128 people (97%) found this review helpful
1 person found this review funny
123.0 hrs on record
Posted: November 10, 2014
Play HL2 maps with your friends. It's like HL2 except multiplayer. It's like GMOD except without the 10 minute loading times
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85 of 87 people (98%) found this review helpful
1 person found this review funny
4.1 hrs on record
Posted: November 15, 2014
Its like HL2 but without the "alone" feeling
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46 of 46 people (100%) found this review helpful
1 person found this review funny
3.5 hrs on record
Posted: November 7, 2014
A really well made mod for Half-Life Co-Op. It breathes some new life into the almost 10 year old game.
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33 of 33 people (100%) found this review helpful
3 people found this review funny
9.5 hrs on record
Posted: January 2
When 15 of the one and only Gordan Freeman run into a hallway and simultaneously get whacked unconcious by the same cop, you know it's gonna be a good game. You start your journey by cooperatively breaking the mini teleporter in Kleiner's lab faster than a 10 year old on xbox live can realise when his internet has just cut out. Proceed to race your fellow chums to numerous respawning copies of the same laser mounted airboat before you have to wait in line with nothing but the sound your crowbar makes when it hits other players to entertain yourself. Stomp all over that antlion awaking sand because you brought an army this time and no one gives a ♥♥♥♥ about whether or not that rebel loser's friend is gonna get killed due to your lack of self reserve. Get vaporized at least 50 times in the combine elevators from violent swarms of electric balls launched by your cackling comrades. Lastly, break the shock and awe that resides in the silence of the game's final, time stopping, life endangering, jaw dropping, moments with a subtle "sometimes I dream about cheese" sounded off by using your keen dialogue wheel. 99/10, A player took out a whole server with an explosive barrel and followed it up by singing the national anthem.
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34 of 35 people (97%) found this review helpful
1 person found this review funny
358.8 hrs on record
Posted: November 5, 2014
Half Life 2 and GTA: San Andreas have a few things in common - they're both single player, they were both released in 2004, they're two of the best games ever made, but best of all: they both had communities which were technically capable of creating multiplayer experiences. GTA SA has Multi Theft Auto and HL2 has Synergy!

As well as being able to experience the whole HL2 story with your friends you're able to play a variety of other co-operative maps and you can even make one yourself with Hammer. Like any modification though, Synergy is not perfect. Server stability was bad and there are some annoying bugs like not being able to pickup ammo. But these problems won't stop you from experiencing a co-operative HL2 campaign.
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21 of 22 people (95%) found this review helpful
1 person found this review funny
11.1 hrs on record
Posted: November 20, 2014
Multiplayer HL2. Can you explain much more?
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19 of 21 people (90%) found this review helpful
1 person found this review funny
3.7 hrs on record
Posted: February 26
Synergy is not a game, Synergy is a mod for a couple of games that allows you to play Online.
I played Synergy with my best friend, Origibro, here on steam.
I enjoyed it very much, we played Half Life 2, we started from the beggining of the game.
Everything is same as playing in Single Player, only is that it's alot better playing with a friend or two.
I hope I continue playing this awesome mod, and I hope my friends want to play it with me as well!

My Rate: 11/10 Awesome.
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16 of 16 people (100%) found this review helpful
1 person found this review funny
22.5 hrs on record
Posted: November 8, 2014
Cool mod. Adds vehicles, weapons, and co-op to an already great game.

10/10 LET ME DRIVE THE JEEEEEEEP!
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16 of 16 people (100%) found this review helpful
1.4 hrs on record
Posted: November 1, 2014
While a bit buggy, a great game for people who love co-op, but want to play HL2
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19 of 22 people (86%) found this review helpful
1 person found this review funny
9.2 hrs on record
Posted: November 15, 2014
5/5
Was this review helpful? Yes No Funny
11 of 11 people (100%) found this review helpful
11 people found this review funny
18.3 hrs on record
Posted: March 31
Pick up that can: Now with friends
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9 of 9 people (100%) found this review helpful
1 person found this review funny
3.2 hrs on record
Posted: December 3, 2014
When I found this I was so happy because i could play all my favourite valve games with my friends. thanks random people who made this!!!! ='D
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9 of 9 people (100%) found this review helpful
2.3 hrs on record
Posted: February 2
This is a must have for fans of Half-Life 2!

To put it short, this is a mod that let's you play Half-Life 2, Half-Life 2: Episode 1, and Half-Life 2: Episode 2 and let's you play it co-op!

How is that not awesome?!

If you have Half-Life 2 GET THIS NOW!
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8 of 8 people (100%) found this review helpful
1 person found this review funny
8.4 hrs on record
Posted: December 16, 2014
Nothing like getting a bunch of friends to hop in the back of a truck on the coast and then speeding around in a mad antlion massacre.
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8 of 8 people (100%) found this review helpful
1 person found this review funny
9.9 hrs on record
Posted: February 16
A Half Life 2 coop mod its free and very awesome.
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11 of 14 people (79%) found this review helpful
1 person found this review funny
30.1 hrs on record
Posted: November 1, 2014
♥♥♥♥ing awesome bro
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8 of 9 people (89%) found this review helpful
1 person found this review funny
25.1 hrs on record
Posted: December 13, 2014
wet dream/10
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6 of 6 people (100%) found this review helpful
48.6 hrs on record
Posted: December 20, 2014
Strapped for cash? Want to play something that is fun?

Get a copy of HL2, and grab this.

You certianly won't regret it.

It's a free mod for HL2 that adds co-op, a few weapons and slight gameplay changes that don't alter the original gameplay too much.

9/10
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5 of 5 people (100%) found this review helpful
1 person found this review funny
1.5 hrs on record
Posted: April 24
Half life 2 multiplayer mod Makes Half life something else
10/10
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4 of 4 people (100%) found this review helpful
1 person found this review funny
12.3 hrs on record
Posted: November 1, 2014
good mod to play half-life 2 with friends
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