Audiosurf is a music-adapting puzzle racer where you use your own music to create your own experience. The shape, the speed, and the mood of each ride is determined by the song you choose. You earn points for clustering together blocks of the same color on the highway, and compete with others on the internet for the high score on your favorite songs. Audiosurf on Steam includes The Orange Box soundtrack, integrated with the game to enable "Still Alive" surfing and more. In addition, Audiosurf is one of the first titles to leverage Steamworks, offering full support for the Steam Achievements that appear on Steam Community profile pages.

Auditorium Duet is the cooperative multiplayer sequel to Auditorium. Bend light and fill music containers in harmony with a partner!

Cooperative Multiplayer <ul class="bb_ul"> <li>Revive, heal, damage boost, raise defense, and remove debuffs from your allies. Reduce the defense and remove buffs from the enemies. </li><li>Online multiplayer with no limit on the amount of players. </li></ul>In-Depth Mechanics <ul class="bb_ul"> <li>Clear dungeons to gain Ability Points, and unlock new abilities. </li><li>Gain Skill Points when leveling up, and use them to enhance those abilities. </li><li>Find synergy between abilities and skills. </li></ul>High Difficulty <ul class="bb_ul"> <li>Challenging game mechanics to master. </li><li>Get swarmed by enemies; each with differing attacks. </li><li>Face hard hitting bosses, with several devastating attacks. </li><li>Avoid environmental dangers, such as lava and chasms. </li><li>Survive with a fragile amount of HP. </li></ul>PVP <ul class="bb_ul"> <li>Battle in a free-for-all with other players. </li><li>Respawn instantly for constant action. </li></ul>Fast-Paced <ul class="bb_ul"> <li>Immediately get back into the action after a game over, with frequent checkpoints and no loading times. </li><li>Damage enemies/bosses and avoid their attacks, at the same time. </li><li>Enemies and bosses are always vulnerable, and have attacks that require quick reflexes to avoid. </li></ul>Customization <ul class="bb_ul"> <li>Set your name, and its color. </li><li>Gain Equipment Points by leveling up and completing dungeons, to unlock and equip upgraded swords and shields. </li></ul>

Aurelia: Stellar Arising - 3D Turn-based Fleet vs. Fleet Space Combat Game. Choose between two factions and fight for control of the Aurelia System in over 77 missions per faction. Control fleets of up to 9 ships and give maneuver and tactical commands to each ship. 
 
Fight through 2 campaigns with 7 phases and 11 missions each to earn maximum rewards and unlock new ships and powerful new upgrades. 150+ Missions to experience and master. 20 total ships (10 per faction) and 18 ship specific upgrades. 
 
Supports 3 different major game modes (Hybrid-Combat, Turn-Based, Team Turns). 5 Levels of difficulty for mission and campaign play. Additional campaign and battle customization options include support for Arcade, Balanced, and Simulation modes as well as Basic and Advanced AI. Play modes include Player Vs. AI, Player Vs. Player, and AI Vs. AI. 
 
Includes a custom battle mode to configure user created battles with full customization of a fleet battle simulator. Enjoy a vast variety of configurations to create your own 9v9 battle simulation. Chose from 19 different battle deployment settings that include: Random, Head-2-Head, Chase/Chased, Back-2-Back, 2x Parallels, 4x Flanks, 8x Obliques with advantageous and disadvantaged positions. 
 
Command &amp; Control 20 Unique Ships - Classes: Gunship, Patrol Craft, Corvette, Frigate, Destroyer – 2 Types of each per faction for a total of 20 unique ships. 
Engage Enemies with 10x Unique Weapon Systems That Consist Of: Auto-Cannons, Auxiliary Batteries, Main Batteries, Missile Launchers, Torpedo Launchers With 100x Ballistic Configurations. 
 
Utilize the Fleet Manager to customize your fleet with hundreds of formation combinations. War Factory to purchase new ships and sell no longer used ships. Ship Viewer to upgrade your ships with over ship specific upgrades.

Aurendor is an open world survival game set on a large island that requires players to test their survival and crafting skills. Players must gather resources, cook their food and fight dangerous creatures on the island. 
 
There are many different types of resources in the game. Trees, stones, mines and plants are vital to players' survival. To collect and use these resources, players need to craft different tools and equipment that they can use skillfully. 
 
Players' cooking skills also play an important role in the survival process. Players can replenish their health points by cooking various dishes. 
 
Aurendor offers players the option of multiplayer gameplay. Players can play together by cooperating with or battling other survivors. You can form a bigger and stronger community by teaming up with your friends, or you can take control of the island by fighting your opponents. 
 
The game's graphics and sound effects have been carefully designed to bring players closer to a real survival experience. Players can enjoy a realistic environment while fighting creatures or interacting with nature. 
 
Aurendor is a great option for players who are interested in survival and crafting games. By playing together with your friends, you have the chance to build a stronger community on the island or fight your opponents.

An amazing mix of RPG, strategy, simulation, sandbox and survival game. Aurora Dusk looks like many other games, but instead of being alone, you live in a community. You can play one or more villagers and evolve from the Wood Age to the Steam Age.

Build anything you can imagine in an infinite world with mountains, rivers and forests. Use tools like copy &amp; paste, undo, redo and other building tools to shape the world from your imagination.<h2 class="bb_tag">Copy &amp; Paste</h2><h2 class="bb_tag">Fill in Area:</h2><h2 class="bb_tag">Undo &amp; Redo:</h2>

Stop the escape of the infected Automata in this asymmetrical co-op tower defense first person shooter game. Choose between playing solo or collaborating with a friend to build defensive structures or face the Automata to avoid their escape.

AV-17 is a FREE 2D action platformer inspired by information technology and BUBBLE BOBBLE!!

Avalon Lords: Dawn Rises is a medieval real time strategy game set in the lands of Spero during the Order of Dawn’s rise to power, featuring a single player RTS campaign and multiplayer battle ground combat.

Get ready, the zombies are coming! Avatar Raiders is a viewer game for Twitch streamers. Your viewers can join the defense against endless waves of zombies. Let your viewers join via your chat, throw emotes or grenades and compete together against a mighty army of super cute zombies.<h2 class="bb_tag">Attention! You must be a Twitch broadcaster to use this product!</h2> Usage: You can include Avatar Raiders as a transparent overlay in your broadcaster software, as well as display it as a full-screen game. Just select the appropriate background scene for your lobby and match, and you're ready to go. No matter if you want to stream the game permanently or if you want to start a match with your viewers only at certain times. The control is yours. Avatar Raiders is also available as a category on Twitch, by the way. Viewer integration: Avatar Raiders connects to your Twitch chat. Your viewers can join a round via chat commands. During the preparation phase, teammates can equip themselves with grenades and use them during the fight. Procedure: A round runs in two phases. Phase 1, Preparation. Your spectators join the game and equip themselves while the countdown displays the remaining time. If you wish, the game characters can also react to chatemotes from the players during this time and throw them in the air. Phase 2, Defense. Teammates advance in waves of a maximum of 10 defenders each and try to stop the advancing zombie hordes. Who will manage to eliminate the most zombies and secure the settlement? Spectators can control when to throw a grenade of their character via chat. At the end of a game round, the points scored are posted once again in the chat.

Team Avatar is back in this action-adventure game! Relive the epic adventure of the original Avatar: The Last Airbender series, as you play as Aang and his friends and master the elements, explore the most unique locations from the series, solve challenging environmental puzzles and experience the most heart touching moments of Aang’s story.​ Play the story solo or with a friend through the game’s unique two-player co-op mode. Embrace Your Destiny and experience Aang’s original adventure. Replay any of the 18 thrilling chapters whenever you choose to experience your favorite moments from the series.

Explore the World of Avatar and travel across the four nations through a 1-2 player co-op 18 chapter adventure.

Play as 9 iconic characters including Aang, Toph, Sokka, and Katara.

Unlock the Mysteries and navigate challenging puzzles using bending and the unique abilities of water, earth, fire and air; upgrade your abilities throughout the story to unleash the full potential of Avatar!

Battle it out with your friends or compete for the title of Grand World Champion in Avian Knights, the crazy game of mounted mayhem combat! Featuring an 8-player competitive arena mode, a classic arcade co-op mode, and tons of weapons and power-ups, there’s plenty of ways to play!

A procedural co-op space sandbox where players can build their own space ships out of dynamically scalable blocks. Fight epic space battles, explore, mine, trade, wage wars and build your own empire to save your galaxy from being torn apart by an unknown enemy.

Have you ever wanted to be a nut? How about a pistachio? Well, now you can! Choose from a wide variety of legumes and assorted nuts as you try flinging into the mouths of your enemies. Play with friends or with complete strangers as 1 human with nut allergies vs. 5 nuts!

The world has never been the same ever since the outbreak happened.
The year is 2032, after the outbreak began, various citizens began their escape from towns, and resorting to
making villages and camps in the woods.
The sources of the virus are unknown, nobody knows why it happened or why it began.
You, among many others, are a survivor who woke up in one of the settlements in the woodlands.
Beware of the zombies, some may be faster or stronger than others.

In the game, you will be managing your stamina, hunger, thirst, O2 and temperature.
Wear warmer clothes if you are in a cold environment, or cook some food with a campfire if you kill an animal and obtain it's raw meat.
You can craft items using the resources you collect in your gameplay, and make a crafting station to craft even more items.
Find a vehicle scattered out in the world and fuel it up with gasoline if it runs out.
With weapons, you can hold the T key to attach any attachment you'd like, as long as it is fit for the weapon category you are using.
Party up with a squad of 5 people (counting you) by clicking the plus icon on the lobby!
Chop down trees using your trusty crafted axe and make wooden planks to create walls and furniture, to create your own base!
Eliminate zombies, players, animals, and gain XP for all of it, you will also be gaining xp for your skill points, which can be used to unlock skills in the skill tree!
There are various options to choose in the character creation menu, from different races to hairstyles, you name it.
In the world, you will find humans just like you! (or not) and some of them may give you quests, or just hang out, or trade with you!

You are stranded on an island, The plane you came with have crashed, and you are alive. To survive on the island you'll have to find food, water and shelter. It's up to you. Do you have the knowledge to know what you can eat or not? 
Are you faster alone but maybe stronger as a team? Decide how you want to play the game. Level your character to increase the skill level. Use your skills on the talent tree to make the character survive the best.

You find yourself in the role of a cruise ship that fell out somewhere in the Indian Ocean. You have to face unforeseen circumstances, get new experience every time in order to ultimately SURVIVE! You have to build a shelter, dive in search of sunken ships, defend yourself from hostile animals, grow crops, and much more.<h2 class="bb_tag">Key features:</h2><ul class="bb_ul"><li>Create your own unique character. </li><li>Look around the island you'll be on when you wake up. </li><li>Stock up on resources and food in order not to starve to death. </li><li>Build a shelter to get through the night safely. </li><li>Hunt. Get ready. </li><li>Build a raft and swim across to neighboring islands. </li><li>Explore and find an opportunity to return to normal life. </li><li>Get Steam achievements, become the top link in the food chain!</li></ul>

The year is 3587. Conflict spans the stars as huge robot armies are locked in an enduring stalemate. In their bid for galactic supremacy, they call upon the most powerful group of mercenaries in the universe: the Awesomenauts! Awesomenauts is a MOBA fitted into the form of an accessible 3-on-3 action platformer. Head out to the online battlefields together with your friends as an online party or in local splitscreen, and never worry about having to wait for an online match because of drop-in matchmaking!

At the end of the 1800s, the government declared a global ban on this legendary card game due to an increase in bar fights, divorces, and family feuds. It was political correctness gone mad.

Brings the rhythm of modern runners to pixel art fantasy battles, with a healthy dose of side-scrolling action and cooperative undead murdering.

Axes and Arrows is an intense action-combat platformer inspired by nostalgic and modern couch multiplayer games.

Axiom Soccer represents a new generation of high-adrenaline digital sports, combining the best of real world ball games and third person shooters. Start scoring goals within minutes, and hone your shooting skills and team tactics to eventually play tournament matches in front of a live, virtual, in-game crowd.

Axon TD infuses a new layer of strategy into Mazing Tower Defenses. Typically, you build towers on the path to obstruct enemies and make the path longer. But what if you could take control of the map layout itself and expand things directly? In Axon TD, you're given a brush, and the map is your canvas!

Best PC Coop Games

Audiosurf

Auditorium 2: Duet

Augury

Aurelia: Stellar Arising

Aurendor

Aurora Dusk: Steam Age

AutoCube

Automata Break

AV-17

Avabel Online

Avalon Lords

Avatar Raiders

Avatar the Last Airbender: Quest for Balance

Avian Knights

Avorion

Aw Nutz

Awakened

Aware

Away From Life

Awesomenauts

Awkward

Axe, Bow & Staff

Axes and Arrows

Axiom Soccer

Axon TD: Uprising - Tower Defense

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