Each server holds up to 8 players, who team up to clear certain objectives together and, of course, kill zombies. NMRH is a survival co-op game taking place in a zombie horror setting. No More Room in Hell Steam Release Trailer

But if you’re in the mood for a competitive shooter in an irradiated, anomaly-blasted landscape and you’re not turned off by the fact it’s still in Early Access or the microtransactions, then Survarium might be just what you need. At the moment, there is only one PvE (tutorial) mission, but the devs have said more are on the way, and PvE game mode is supposed to be a major component of the game. Teams can compete in researching anomalies, collecting batteries or they can engage in artifact hunts. The game sports several game modes in addition to the standard team deathmatch and it’s small-scale, faster-paced variant Slaughter. This is what gives Survarium its own unique feel, allowing it to stand out from many other competitive shooters. Aside from the opposing team, the players also have to contend with the environment, including the mysterious anomalies which will force you to take into account different tactical opportunities and hazards. Gunplay is decent if a bit twitchy, but since the game is still in early access, improvements are expected. However, far from being a vast, irradiated world exploration, this is primarily a small-scale PvP shooter on maps that will seem cramped if you expected another STALKER. Survarium is another free-to-play online game on this list.

Really good free to play games