Games similar to HELLDIVERS include ARC Raiders. It's paid, but Alien Swarm is free. Other options are Teleglitch and Halo:Spartan Strike. In total there are four Open World Games like HELLDIVERS for Windows, Mac and Linux.
ARC Raiders is a multiplayer adventure and extraction game set in a future where Earth is ravaged by a mysterious mechanized threat known as ARC.
Sweden
EU
Alien Swarm is a free top-down shoot-em-up video game by Valve Corporation. It is a remake of the Alien Swarm mod for Unreal Tournament 2004, and it was developed by the original team, which was hired by Valve during the course of the development process.
United States
Teleglitch is a roguelike top-down shooter with pixel graphics. The game takes place in procedurally generated military research & training complex that has a different map every time you play.
Halo: Spartan Strike makes you a Spartan supersoldier battling evil forces. Delve into 30 challenging missions through cities and jungles using a devastating arsenal of weapons, abilities and vehicles including the iconic Warthog against the Covenant and Promethean enemies.
United States
