Tripwire Interactive's first-person shooter, Killing Floor 2, is free-to-play now on Steam through Tuesday, June 25. The free weekend kicks off this summer's Back & Kickin' Brass event, which adds a new mode, map, and weapons, running through July 31. As is usually the case with Steam free weekends, if you like the game and want to keep playing, you can purchase it at a 67% discount to keep it in your library after the weekend ends, retaining any progress that you made.

Back & Kickin' Brass adds a new gameplay mode called Objective, in which players must defeat waves of enemies while also completing particular objectives, such as delivering an object from one point on the map to another. It also adds a new map, the Steam Fortress, which is compatible with the Survival, Weekly, Endless, and new Objective gameplay modes, as well as new weapons, such as the Seal Squealer, which launches exploding harpoons.

First released in 2016, Killing Floor 2 picks up from the story of the first game, in which a mad scientist unleashed an army of clone soldiers onto the UK. Several months following the events of that game, the plague of Zeds had spread around the world, causing global chaos. Most of the action comprises taking on waves of enemies, often culminating in a boss. In his Killing Floor 2 review, GameSpot's Miguel Concepcion found the single-player gameplay to be a little thin, but as a suite of multiplayer modes the game was perfectly satisfying.

Source: GameSpot