The excellent Killing Floor 2 is free on the Epic Games Store

pcgamer.com:

Killing Floor 2 is free on the Epic Games Store for the next week(opens in new tab), and it's some of the best co-op shooting action I've ever played. It's not a dreadfully complex game: you have characters with different abilities and weapons, there are various different enemy types, and they come in waves until you're dead or survive long enough to complete certain objectives.

PCG's Tyler Wilde called Killing Floor 2(opens in new tab) «a visual spectacle, and a challenging, fun co-op shooter with an active mapmaking community. You can play it for the struggle against overwhelming odds, you and a few friends beating back hundreds of hellions, constantly pushed to the edge of death. Or you can play it like I’ve started to, when I’ve had a long day: put on a podcast, join a ridiculous 50-player server on a ridiculous player-made map that includes a literal staircase to heaven, and enjoy the headshots.»

Killing Floor 2 got a handsome 81% in that review: thing is though, that was six years ago and since then the game has been continuously updated(opens in new tab). The freebie on the Epic Store doesn't come with the paid DLC, but there have been plenty of free updates along the way too, and if you've got a few mates who might be interested this is at least a few nights' worth of top quality monster-blasting laughs.

Alongside this, card-battling RPG Ancient Enemy is also free until July 14(opens in new tab). Epic's strategy of offering free titles to get consumers creating Epic Games Store accounts is definitely working, going by its growth in user numbers: but when the freebies it's serving up are as good as Killing Floor 2, no wonder.