Canadian game developer Relic Entertainment would release a free playable co-op mode, called Exterminatus for its upcoming third-person action video game, Warhammer 40,000: Space Marine in early October.

Coming to Space Marine as free DLC in October, the four-player Exterminatus Mode pits an elite squad of four Space Marines against hordes of alien enemies in a score-based fight to the death.

You can choose from the Tactical Marine, Devastator or Assault Marine as well as utilizing any weapons and perks available to those classes, Relic said in a statement.

Each of the Exterminatus scenarios, Assault on Hab Center Andreas and Escape From Kalkys Facility feature multiple arenas, global leader boards, encouraging gamer to take the risk on dynamic in-game challenges that pop up during play.

For example, Kill 10 Orks in 10 seconds. With extra lives and points up for grabs if you complete a challenge. Experience earned while playing this mode also counts towards multiplayer ranks, allowing you to level up in both co-op and multiplayer.

Space Marine is scheduled to be available for Xbox 360, Playstation 3 and Windows PC on Sept. 6.

In the game, players take the role of Captain Titus, a Space Marine. An ork horde is launching an invasion of an Imperial Forge World, a planet-dedicated industry that manufactures vehicles and weaponry for the Imperium's soldiers.

The Warboss, leading the invasion is attempting to steal a vehicle namely Warlord Class Battle Titan. Captain Titus of the Ultramarines Chapter is sent with a small contingent of Ultramarines to slow down the invaders whilst the Liberation fleet prepares a counter assault.

Following are some of Warhammer 40,000: Space Marine - Exterminatus Screenshots: