1,797 Action · Online co-op games your group can play together online, including Sanctum 2, Contagion, and Castle Crashers®.
All games: 24
Sanctum 2 combines tower-defense building and first-person shooting in an online campaign for up to four players. You and your friends protect oxygen-producing Cores through waves, character loadouts, and optional survival runs.
Contagion mixes cooperative zombie survival, a story campaign, and player-versus-player modes. See how its online party, game modes, and older PC setup fit your group.
Castle Crashers sends up to four knights through a comic fantasy campaign, with local and online co-op, magic, weapons, and animal companions.
War Thunder is the most comprehensive free-to-play, cross-platform, MMO military game dedicated to aviation, armoured vehicles, and naval craft, from the early 20th century to the most advanced modern combat units. Join now and take part in major battles on land, in the air, and at sea.
Take on short cooperative Challenges or build beside your friends in team battles, where King Arthur’s Gold makes fortress walls as fragile as your plans.
Gather your fearless allies in the heart-pounding realms of Fiesta Online, where the fate of Isya rests on your shoulders. Prepare to wage war against the malevolent grip of Legel's corruption, forging powerful bonds with fellow adventurers as you embark on quests that will push you to your limits.
Case guarded buildings, grab the valuables, and escape together in Monaco: What's Yours Is Mine, a top-down heist game for up to four players online or on one screen.
Defend generators, buy upgrades between waves, and bring up to four friends into the original five-player co-op modes of ORION: Prelude.
PANZAR is a fantasy multiplayer third-person shooter. You get to choose from eight unique character classes, team-based PvP battles, exciting PvE adventures and regular tournaments with real prizes. Advanced RPG elements, the non-target combat system and the most modern graphics by CryEngine 3 will make your combat experience...
A deep, tactical shoot'em up. With every takedown, you’ll earn cash and xp to upgrade your ship and unlock new abilities. Online and local co-op. Unique versus mode. Realistic physics and water simulation.
Multiplayer is designed for up to ten players, with online and LAN co-op or PvP modes; build empires together against AI rivals and choose from six factions and several match endings.
Defend magical rifts with a friend in a two-player action tower defense game built around traps, weapons, and fast-moving orc waves.
Join up to two friends for a 3v3 platforming MOBA, push through droid lanes, and break the rival team’s base in Awesomenauts.
Join friends in Realm of the Mad God Exalt for crowded online boss fights, branching dungeons, 19 classes, and permanent character loss when a hero falls.
Take on a colorful, weapon-packed FPS campaign with friends online or over LAN, then swap monster waves for versus play.
Build defenses with up to three friends, then fight beside them as monsters swarm the crystal. Dungeon Defenders mixes tower strategy, action combat, and a long trail of character and gear upgrades.
Mine, build, and take on a changing world with your friends in Terraria. A desktop server starts with 16 online player slots; explore for better gear, then bring it into boss fights and invasions together.
Take on the role of a hardened career criminal executing intense, dynamic heists in constant pursuit of the next “big score”
Blast through Serious Sam 3: BFE’s campaign with up to 16 online players or four people in local split-screen, against waves of monsters in Egypt.
DC Universe Online is a Free-to-Play, massive multiplayer online action game set in the popular DC Universe. Become one of a new breed of Heroes or Villains and wield incredible powers as you go to war with legendary characters such as Batman, Superman, Lex Luthor and The Joker.
The "Perpetual Testing Initiative" has been expanded to allow you to design co-op puzzles for you and your friends!
Join The Mobile Trench Brigade and protect humanity from the evil Monovision menace!
The genre-defining military sim that began as Operation Flashpoint (2001), now a modernized, 64-bit, cross-platform build for Windows and Linux, with its engine released as open source. Over 2 million copies sold. The Cold War battlefield of Everon and Nogova, remastered for today's hardware.
Take on a cryptic cyberpunk campaign with up to three friends, mixing firefights, hacking, psychic powers, and character builds.