The free game klaxon is sounding. Should you answer its call within the next seven hours, you'll get a free copy of Wolfire's Receiver. It's a procedurally generated cyberpunk gun sim—modelling a weapon's every available interaction. It's good, and you can get it for nothing from the Humble Store .

In Receiver, you track down a series of tapes across randomly generated levels. Between you and them are a number of autonomous threats, from sentry turrets to hovering patrol bots. No big deal, you just need to shoot them, right? Yeah, kind of.

Each separate weapon interaction is mapped to a different key. To reload, you don't just press 'R', but rather a series of keys to eject, discard and replace a magazine. Whereas in most games, guns are a magical conduit for a character's ability to murder up his foes, in Receiver, guns are just a machine to be operated.

Head over to the Humble Store to get your free copy. Once redeemed, the game can optionally be activated through Steam.